Category Archives: Chemical Elements

Synthesis of a new element with atomic number Z=117

A paper has just been accepted (5 April 2010) for publication in Physical Review Letters.1

International team discovers element 117
A new chemical element has been added to the Periodic Table: A paper on the discovery of element 117 has been accepted for publication in Physical Review Letters.

Oak Ridge National Laboratory is part of a team that includes the Joint Institute of Nuclear Research (Dubna, Russia), the Research Institute for Advanced Reactors (Dimitrovgrad), Lawrence Livermore National Laboratory, Vanderbilt University and the University of Nevada Las Vegas. ORNL’s role included production of the berkelium-249 isotope necessary for the target, which was subjected to an extended, months-long run at the heavy ion accelerator facility at Dubna, Russia.

“Without the berkelium target, there could have been no experiment,” says ORNL Director of Strategic Capabilities Jim Roberto, who is a principal author on the PRL paper and who helped initiate the experiment. The berkelium was produced at the High Flux Isotope Reactor and processed at the adjoining Radiochemical Engineering & Development Laboratory as part of the most recent campaign to produce californium-252, a radioisotope widely used in industry and medicine.

“Russia had proposed this experiment in 2004, but since we had no californium production at the time, we couldn’t supply the berkelium. With the initiation of californium production in 2008, we were able to implement a collaboration,” Roberto says.
Professor Joe Hamilton of Vanderbilt University (who helped establish the Joint Institute for Heavy Ion Research at ORNL) introduced Roberto to Yuri Oganessian of Russia’s JINR. Five months of the Dubna JINR U400 accelerator’s calcium-48 beam – one of the world’s most powerful – was dedicated to the project.

The massive effort identified a total of six atoms of element 117 and the critical reams of data that substantiate their existence.
The two-year experimental campaign began with a 250-day irradiation in HFIR, producing 22 milligrams of berkelium-249, which has a 320-day half-life. The irradiation was followed by 90 days of processing at REDC to separate and purify the berkelium. The Bk-249 target was prepared at Dimitrovgrad and then bombarded for 150 days at the Dubna facility. Lawrence Livermore, which now has been involved in the discovery of six elements with Dubna (113, 114, 115, 116, 117, and 118), contributed data analysis, and the entire team was involved in the assessment of the results.

This is the second element that ORNL has had a role in discovering, joining element 61, promethium, which was discovered at the Graphite Reactor during the Manhattan project and reported in 1946. ORNL, by way of its production of radioisotopes for research, has contributed to the discovery of a total of seven new elements.

Members of the ORNL team include the Physics Division’s Krzysztof Rykaczewsi, Porter Bailey of the Nonreactor Nuclear Facilities Division, and Dennis Benker, Julie Ezold, Curtis Porter and Frank Riley of the Nuclear S&T Division. Roberto says the success of the element-117 campaign underscores the value of international collaborations in science.
“This use of ORNL isotopes and Russian accelerators is a tremendous example of the value of working together,” he says. “The 117 experiment paired one of the world’s leading research reactors–capable of producing the berkelium target material–with the exceptional heavy ion accelerator and detection capabilities at Dubna.”

Islands of Stability

Roberto also says the experiment, in addition to discovering a new chemical element, has pushed the Periodic Table further into the neutron-rich regime for heaviest elements. “New isotopes observed in these experiments continue a trend toward higher lifetimes for increased neutron numbers, providing evidence for the proposed “island of stability” for super-heavy nuclei,” he says. “Because the half-lives are getting longer, there is potential to study the chemistry of these nuclei,” Roberto says. “These experiments and discoveries essentially open new frontiers of chemistry.”

—Bill Cabage

The news about the claim was announced in a press release from the Oak Ridge National Laboratory.

Element 117 discovered?

On 1 May 2014 a paper published in Phys. Rev. Lett by J. Khuyagbaatar and others states the superheavy element with atomic number Z = 117 (ununseptium) was produced as an evaporation residue in the 48Ca and 249Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allows measurement of decays of single atomic nuclei with very short half-lives . Two decay chains comprising seven α-decays and a spontaneous fission each were identified and assigned to the isotope 294Uus (element 117) and its decay products.

This reinforces a paper published 5 April 2010 in Physical Review Letters by Yu. Ts. Oganessian and others claims the synthesis of a new element with atomic number 117. The abstract states “The discovery of a new chemical element with atomic number Z=117 is reported. The isotopes 293117 and 294117 were produced in fusion reactions between 48Ca and 249Bk. Decay chains involving eleven new nuclei were identified by means of the Dubna Gas Filled Recoil Separator. The measured decay properties show a strong rise of stability for heavier isotopes with Z>=111, validating the concept of the long sought island of enhanced stability for super-heavy nuclei.” Read more: Physical Review Letters: element 117 preliminary publication

Fundamental Physical Constants — Complete Listing

  Quantity                                                       Value                 Uncertainty           Unit
-----------------------------------------------------------------------------------------------------------------------------
{220} lattice spacing of silicon                            192.015 5714 e-12        0.000 0032 e-12          m
alpha particle-electron mass ratio                          7294.299 5361            0.000 0029               
alpha particle mass                                         6.644 656 75 e-27        0.000 000 29 e-27        kg
alpha particle mass energy equivalent                       5.971 919 67 e-10        0.000 000 26 e-10        J
alpha particle mass energy equivalent in MeV                3727.379 240             0.000 082                MeV
alpha particle mass in u                                    4.001 506 179 125        0.000 000 000 062        u
alpha particle molar mass                                   4.001 506 179 125 e-3    0.000 000 000 062 e-3    kg mol^-1
alpha particle-proton mass ratio                            3.972 599 689 33         0.000 000 000 36         
Angstrom star                                               1.000 014 95 e-10        0.000 000 90 e-10        m
atomic mass constant                                        1.660 538 921 e-27       0.000 000 073 e-27       kg
atomic mass constant energy equivalent                      1.492 417 954 e-10       0.000 000 066 e-10       J
atomic mass constant energy equivalent in MeV               931.494 061              0.000 021                MeV
atomic mass unit-electron volt relationship                 931.494 061 e6           0.000 021 e6             eV
atomic mass unit-hartree relationship                       3.423 177 6845 e7        0.000 000 0024 e7        E_h
atomic mass unit-hertz relationship                         2.252 342 7168 e23       0.000 000 0016 e23       Hz
atomic mass unit-inverse meter relationship                 7.513 006 6042 e14       0.000 000 0053 e14       m^-1
atomic mass unit-joule relationship                         1.492 417 954 e-10       0.000 000 066 e-10       J
atomic mass unit-kelvin relationship                        1.080 954 08 e13         0.000 000 98 e13         K
atomic mass unit-kilogram relationship                      1.660 538 921 e-27       0.000 000 073 e-27       kg
atomic unit of 1st hyperpolarizability                      3.206 361 449 e-53       0.000 000 071 e-53       C^3 m^3 J^-2
atomic unit of 2nd hyperpolarizability                      6.235 380 54 e-65        0.000 000 28 e-65        C^4 m^4 J^-3
atomic unit of action                                       1.054 571 726 e-34       0.000 000 047 e-34       J s
atomic unit of charge                                       1.602 176 565 e-19       0.000 000 035 e-19       C
atomic unit of charge density                               1.081 202 338 e12        0.000 000 024 e12        C m^-3
atomic unit of current                                      6.623 617 95 e-3         0.000 000 15 e-3         A
atomic unit of electric dipole mom.                         8.478 353 26 e-30        0.000 000 19 e-30        C m
atomic unit of electric field                               5.142 206 52 e11         0.000 000 11 e11         V m^-1
atomic unit of electric field gradient                      9.717 362 00 e21         0.000 000 21 e21         V m^-2
atomic unit of electric polarizability                      1.648 777 2754 e-41      0.000 000 0016 e-41      C^2 m^2 J^-1
atomic unit of electric potential                           27.211 385 05            0.000 000 60             V
atomic unit of electric quadrupole mom.                     4.486 551 331 e-40       0.000 000 099 e-40       C m^2
atomic unit of energy                                       4.359 744 34 e-18        0.000 000 19 e-18        J
atomic unit of force                                        8.238 722 78 e-8         0.000 000 36 e-8         N
atomic unit of length                                       0.529 177 210 92 e-10    0.000 000 000 17 e-10    m
atomic unit of mag. dipole mom.                             1.854 801 936 e-23       0.000 000 041 e-23       J T^-1
atomic unit of mag. flux density                            2.350 517 464 e5         0.000 000 052 e5         T
atomic unit of magnetizability                              7.891 036 607 e-29       0.000 000 013 e-29       J T^-2
atomic unit of mass                                         9.109 382 91 e-31        0.000 000 40 e-31        kg
atomic unit of mom.um                                       1.992 851 740 e-24       0.000 000 088 e-24       kg m s^-1
atomic unit of permittivity                                 1.112 650 056... e-10    (exact)                  F m^-1
atomic unit of time                                         2.418 884 326 502 e-17   0.000 000 000 012 e-17   s
atomic unit of velocity                                     2.187 691 263 79 e6      0.000 000 000 71 e6      m s^-1
Avogadro constant                                           6.022 141 29 e23         0.000 000 27 e23         mol^-1
Bohr magneton                                               927.400 968 e-26         0.000 020 e-26           J T^-1
Bohr magneton in eV/T                                       5.788 381 8066 e-5       0.000 000 0038 e-5       eV T^-1
Bohr magneton in Hz/T                                       13.996 245 55 e9         0.000 000 31 e9          Hz T^-1
Bohr magneton in inverse meters per tesla                   46.686 4498              0.000 0010               m^-1 T^-1
Bohr magneton in K/T                                        0.671 713 88             0.000 000 61             K T^-1
Bohr radius                                                 0.529 177 210 92 e-10    0.000 000 000 17 e-10    m
Boltzmann constant                                          1.380 6488 e-23          0.000 0013 e-23          J K^-1
Boltzmann constant in eV/K                                  8.617 3324 e-5           0.000 0078 e-5           eV K^-1
Boltzmann constant in Hz/K                                  2.083 6618 e10           0.000 0019 e10           Hz K^-1
Boltzmann constant in inverse meters per kelvin             69.503 476               0.000 063                m^-1 K^-1
characteristic impedance of vacuum                          376.730 313 461...       (exact)                  ohm
classical electron radius                                   2.817 940 3267 e-15      0.000 000 0027 e-15      m
Compton wavelength                                          2.426 310 2389 e-12      0.000 000 0016 e-12      m
Compton wavelength over 2 pi                                386.159 268 00 e-15      0.000 000 25 e-15        m
conductance quantum                                         7.748 091 7346 e-5       0.000 000 0025 e-5       S
conventional value of Josephson constant                    483 597.9 e9             (exact)                  Hz V^-1
conventional value of von Klitzing constant                 25 812.807               (exact)                  ohm
Cu x unit                                                   1.002 076 97 e-13        0.000 000 28 e-13        m
deuteron-electron mag. mom. ratio                           -4.664 345 537 e-4       0.000 000 039 e-4        
deuteron-electron mass ratio                                3670.482 9652            0.000 0015               
deuteron g factor                                           0.857 438 2308           0.000 000 0072           
deuteron mag. mom.                                          0.433 073 489 e-26       0.000 000 010 e-26       J T^-1
deuteron mag. mom. to Bohr magneton ratio                   0.466 975 4556 e-3       0.000 000 0039 e-3       
deuteron mag. mom. to nuclear magneton ratio                0.857 438 2308           0.000 000 0072           
deuteron mass                                               3.343 583 48 e-27        0.000 000 15 e-27        kg
deuteron mass energy equivalent                             3.005 062 97 e-10        0.000 000 13 e-10        J
deuteron mass energy equivalent in MeV                      1875.612 859             0.000 041                MeV
deuteron mass in u                                          2.013 553 212 712        0.000 000 000 077        u
deuteron molar mass                                         2.013 553 212 712 e-3    0.000 000 000 077 e-3    kg mol^-1
deuteron-neutron mag. mom. ratio                            -0.448 206 52            0.000 000 11             
deuteron-proton mag. mom. ratio                             0.307 012 2070           0.000 000 0024           
deuteron-proton mass ratio                                  1.999 007 500 97         0.000 000 000 18         
deuteron rms charge radius                                  2.1424 e-15              0.0021 e-15              m
electric constant                                           8.854 187 817... e-12    (exact)                  F m^-1
electron charge to mass quotient                            -1.758 820 088 e11       0.000 000 039 e11        C kg^-1
electron-deuteron mag. mom. ratio                           -2143.923 498            0.000 018                
electron-deuteron mass ratio                                2.724 437 1095 e-4       0.000 000 0011 e-4       
electron g factor                                           -2.002 319 304 361 53    0.000 000 000 000 53     
electron gyromag. ratio                                     1.760 859 708 e11        0.000 000 039 e11        s^-1 T^-1
electron gyromag. ratio over 2 pi                           28 024.952 66            0.000 62                 MHz T^-1
electron-helion mass ratio                                  1.819 543 0761 e-4       0.000 000 0017 e-4       
electron mag. mom.                                          -928.476 430 e-26        0.000 021 e-26           J T^-1
electron mag. mom. anomaly                                  1.159 652 180 76 e-3     0.000 000 000 27 e-3     
electron mag. mom. to Bohr magneton ratio                   -1.001 159 652 180 76    0.000 000 000 000 27     
electron mag. mom. to nuclear magneton ratio                -1838.281 970 90         0.000 000 75             
electron mass                                               9.109 382 91 e-31        0.000 000 40 e-31        kg
electron mass energy equivalent                             8.187 105 06 e-14        0.000 000 36 e-14        J
electron mass energy equivalent in MeV                      0.510 998 928            0.000 000 011            MeV
electron mass in u                                          5.485 799 0946 e-4       0.000 000 0022 e-4       u
electron molar mass                                         5.485 799 0946 e-7       0.000 000 0022 e-7       kg mol^-1
electron-muon mag. mom. ratio                               206.766 9896             0.000 0052               
electron-muon mass ratio                                    4.836 331 66 e-3         0.000 000 12 e-3         
electron-neutron mag. mom. ratio                            960.920 50               0.000 23                 
electron-neutron mass ratio                                 5.438 673 4461 e-4       0.000 000 0032 e-4       
electron-proton mag. mom. ratio                             -658.210 6848            0.000 0054               
electron-proton mass ratio                                  5.446 170 2178 e-4       0.000 000 0022 e-4       
electron-tau mass ratio                                     2.875 92 e-4             0.000 26 e-4             
electron to alpha particle mass ratio                       1.370 933 555 78 e-4     0.000 000 000 55 e-4     
electron to shielded helion mag. mom. ratio                 864.058 257              0.000 010                
electron to shielded proton mag. mom. ratio                 -658.227 5971            0.000 0072               
electron-triton mass ratio                                  1.819 200 0653 e-4       0.000 000 0017 e-4       
electron volt                                               1.602 176 565 e-19       0.000 000 035 e-19       J
electron volt-atomic mass unit relationship                 1.073 544 150 e-9        0.000 000 024 e-9        u
electron volt-hartree relationship                          3.674 932 379 e-2        0.000 000 081 e-2        E_h
electron volt-hertz relationship                            2.417 989 348 e14        0.000 000 053 e14        Hz
electron volt-inverse meter relationship                    8.065 544 29 e5          0.000 000 18 e5          m^-1
electron volt-joule relationship                            1.602 176 565 e-19       0.000 000 035 e-19       J
electron volt-kelvin relationship                           1.160 4519 e4            0.000 0011 e4            K
electron volt-kilogram relationship                         1.782 661 845 e-36       0.000 000 039 e-36       kg
elementary charge                                           1.602 176 565 e-19       0.000 000 035 e-19       C
elementary charge over h                                    2.417 989 348 e14        0.000 000 053 e14        A J^-1
Faraday constant                                            96 485.3365              0.0021                   C mol^-1
Faraday constant for conventional electric current          96 485.3321              0.0043                   C_90 mol^-1
Fermi coupling constant                                     1.166 364 e-5            0.000 005 e-5            GeV^-2
fine-structure constant                                     7.297 352 5698 e-3       0.000 000 0024 e-3       
first radiation constant                                    3.741 771 53 e-16        0.000 000 17 e-16        W m^2
first radiation constant for spectral radiance              1.191 042 869 e-16       0.000 000 053 e-16       W m^2 sr^-1
hartree-atomic mass unit relationship                       2.921 262 3246 e-8       0.000 000 0021 e-8       u
hartree-electron volt relationship                          27.211 385 05            0.000 000 60             eV
Hartree energy                                              4.359 744 34 e-18        0.000 000 19 e-18        J
Hartree energy in eV                                        27.211 385 05            0.000 000 60             eV
hartree-hertz relationship                                  6.579 683 920 729 e15    0.000 000 000 033 e15    Hz
hartree-inverse meter relationship                          2.194 746 313 708 e7     0.000 000 000 011 e7     m^-1
hartree-joule relationship                                  4.359 744 34 e-18        0.000 000 19 e-18        J
hartree-kelvin relationship                                 3.157 7504 e5            0.000 0029 e5            K
hartree-kilogram relationship                               4.850 869 79 e-35        0.000 000 21 e-35        kg
helion-electron mass ratio                                  5495.885 2754            0.000 0050               
helion g factor                                             -4.255 250 613           0.000 000 050            
helion mag. mom.                                            -1.074 617 486 e-26      0.000 000 027 e-26       J T^-1
helion mag. mom. to Bohr magneton ratio                     -1.158 740 958 e-3       0.000 000 014 e-3        
helion mag. mom. to nuclear magneton ratio                  -2.127 625 306           0.000 000 025            
helion mass                                                 5.006 412 34 e-27        0.000 000 22 e-27        kg
helion mass energy equivalent                               4.499 539 02 e-10        0.000 000 20 e-10        J
helion mass energy equivalent in MeV                        2808.391 482             0.000 062                MeV
helion mass in u                                            3.014 932 2468           0.000 000 0025           u
helion molar mass                                           3.014 932 2468 e-3       0.000 000 0025 e-3       kg mol^-1
helion-proton mass ratio                                    2.993 152 6707           0.000 000 0025           
hertz-atomic mass unit relationship                         4.439 821 6689 e-24      0.000 000 0031 e-24      u
hertz-electron volt relationship                            4.135 667 516 e-15       0.000 000 091 e-15       eV
hertz-hartree relationship                                  1.519 829 846 0045 e-16  0.000 000 000 0076 e-16  E_h
hertz-inverse meter relationship                            3.335 640 951... e-9     (exact)                  m^-1
hertz-joule relationship                                    6.626 069 57 e-34        0.000 000 29 e-34        J
hertz-kelvin relationship                                   4.799 2434 e-11          0.000 0044 e-11          K
hertz-kilogram relationship                                 7.372 496 68 e-51        0.000 000 33 e-51        kg
inverse fine-structure constant                             137.035 999 074          0.000 000 044            
inverse meter-atomic mass unit relationship                 1.331 025 051 20 e-15    0.000 000 000 94 e-15    u
inverse meter-electron volt relationship                    1.239 841 930 e-6        0.000 000 027 e-6        eV
inverse meter-hartree relationship                          4.556 335 252 755 e-8    0.000 000 000 023 e-8    E_h
inverse meter-hertz relationship                            299 792 458              (exact)                  Hz
inverse meter-joule relationship                            1.986 445 684 e-25       0.000 000 088 e-25       J
inverse meter-kelvin relationship                           1.438 7770 e-2           0.000 0013 e-2           K
inverse meter-kilogram relationship                         2.210 218 902 e-42       0.000 000 098 e-42       kg
inverse of conductance quantum                              12 906.403 7217          0.000 0042               ohm
Josephson constant                                          483 597.870 e9           0.011 e9                 Hz V^-1
joule-atomic mass unit relationship                         6.700 535 85 e9          0.000 000 30 e9          u
joule-electron volt relationship                            6.241 509 34 e18         0.000 000 14 e18         eV
joule-hartree relationship                                  2.293 712 48 e17         0.000 000 10 e17         E_h
joule-hertz relationship                                    1.509 190 311 e33        0.000 000 067 e33        Hz
joule-inverse meter relationship                            5.034 117 01 e24         0.000 000 22 e24         m^-1
joule-kelvin relationship                                   7.242 9716 e22           0.000 0066 e22           K
joule-kilogram relationship                                 1.112 650 056... e-17    (exact)                  kg
kelvin-atomic mass unit relationship                        9.251 0868 e-14          0.000 0084 e-14          u
kelvin-electron volt relationship                           8.617 3324 e-5           0.000 0078 e-5           eV
kelvin-hartree relationship                                 3.166 8114 e-6           0.000 0029 e-6           E_h
kelvin-hertz relationship                                   2.083 6618 e10           0.000 0019 e10           Hz
kelvin-inverse meter relationship                           69.503 476               0.000 063                m^-1
kelvin-joule relationship                                   1.380 6488 e-23          0.000 0013 e-23          J
kelvin-kilogram relationship                                1.536 1790 e-40          0.000 0014 e-40          kg
kilogram-atomic mass unit relationship                      6.022 141 29 e26         0.000 000 27 e26         u
kilogram-electron volt relationship                         5.609 588 85 e35         0.000 000 12 e35         eV
kilogram-hartree relationship                               2.061 485 968 e34        0.000 000 091 e34        E_h
kilogram-hertz relationship                                 1.356 392 608 e50        0.000 000 060 e50        Hz
kilogram-inverse meter relationship                         4.524 438 73 e41         0.000 000 20 e41         m^-1
kilogram-joule relationship                                 8.987 551 787... e16     (exact)                  J
kilogram-kelvin relationship                                6.509 6582 e39           0.000 0059 e39           K
lattice parameter of silicon                                543.102 0504 e-12        0.000 0089 e-12          m
Loschmidt constant (273.15 K, 100 kPa)                      2.651 6462 e25           0.000 0024 e25           m^-3
Loschmidt constant (273.15 K, 101.325 kPa)                  2.686 7805 e25           0.000 0024 e25           m^-3
mag. constant                                               12.566 370 614... e-7    (exact)                  N A^-2
mag. flux quantum                                           2.067 833 758 e-15       0.000 000 046 e-15       Wb
molar gas constant                                          8.314 4621               0.000 0075               J mol^-1 K^-1
molar mass constant                                         1 e-3                    (exact)                  kg mol^-1
molar mass of carbon-12                                     12 e-3                   (exact)                  kg mol^-1
molar Planck constant                                       3.990 312 7176 e-10      0.000 000 0028 e-10      J s mol^-1
molar Planck constant times c                               0.119 626 565 779        0.000 000 000 084        J m mol^-1
molar volume of ideal gas (273.15 K, 100 kPa)               22.710 953 e-3           0.000 021 e-3            m^3 mol^-1
molar volume of ideal gas (273.15 K, 101.325 kPa)           22.413 968 e-3           0.000 020 e-3            m^3 mol^-1
molar volume of silicon                                     12.058 833 01 e-6        0.000 000 80 e-6         m^3 mol^-1
Mo x unit                                                   1.002 099 52 e-13        0.000 000 53 e-13        m
muon Compton wavelength                                     11.734 441 03 e-15       0.000 000 30 e-15        m
muon Compton wavelength over 2 pi                           1.867 594 294 e-15       0.000 000 047 e-15       m
muon-electron mass ratio                                    206.768 2843             0.000 0052               
muon g factor                                               -2.002 331 8418          0.000 000 0013           
muon mag. mom.                                              -4.490 448 07 e-26       0.000 000 15 e-26        J T^-1
muon mag. mom. anomaly                                      1.165 920 91 e-3         0.000 000 63 e-3         
muon mag. mom. to Bohr magneton ratio                       -4.841 970 44 e-3        0.000 000 12 e-3         
muon mag. mom. to nuclear magneton ratio                    -8.890 596 97            0.000 000 22             
muon mass                                                   1.883 531 475 e-28       0.000 000 096 e-28       kg
muon mass energy equivalent                                 1.692 833 667 e-11       0.000 000 086 e-11       J
muon mass energy equivalent in MeV                          105.658 3715             0.000 0035               MeV
muon mass in u                                              0.113 428 9267           0.000 000 0029           u
muon molar mass                                             0.113 428 9267 e-3       0.000 000 0029 e-3       kg mol^-1
muon-neutron mass ratio                                     0.112 454 5177           0.000 000 0028           
muon-proton mag. mom. ratio                                 -3.183 345 107           0.000 000 084            
muon-proton mass ratio                                      0.112 609 5272           0.000 000 0028           
muon-tau mass ratio                                         5.946 49 e-2             0.000 54 e-2             
natural unit of action                                      1.054 571 726 e-34       0.000 000 047 e-34       J s
natural unit of action in eV s                              6.582 119 28 e-16        0.000 000 15 e-16        eV s
natural unit of energy                                      8.187 105 06 e-14        0.000 000 36 e-14        J
natural unit of energy in MeV                               0.510 998 928            0.000 000 011            MeV
natural unit of length                                      386.159 268 00 e-15      0.000 000 25 e-15        m
natural unit of mass                                        9.109 382 91 e-31        0.000 000 40 e-31        kg
natural unit of mom.um                                      2.730 924 29 e-22        0.000 000 12 e-22        kg m s^-1
natural unit of mom.um in MeV/c                             0.510 998 928            0.000 000 011            MeV/c
natural unit of time                                        1.288 088 668 33 e-21    0.000 000 000 83 e-21    s
natural unit of velocity                                    299 792 458              (exact)                  m s^-1
neutron Compton wavelength                                  1.319 590 9068 e-15      0.000 000 0011 e-15      m
neutron Compton wavelength over 2 pi                        0.210 019 415 68 e-15    0.000 000 000 17 e-15    m
neutron-electron mag. mom. ratio                            1.040 668 82 e-3         0.000 000 25 e-3         
neutron-electron mass ratio                                 1838.683 6605            0.000 0011               
neutron g factor                                            -3.826 085 45            0.000 000 90             
neutron gyromag. ratio                                      1.832 471 79 e8          0.000 000 43 e8          s^-1 T^-1
neutron gyromag. ratio over 2 pi                            29.164 6943              0.000 0069               MHz T^-1
neutron mag. mom.                                           -0.966 236 47 e-26       0.000 000 23 e-26        J T^-1
neutron mag. mom. to Bohr magneton ratio                    -1.041 875 63 e-3        0.000 000 25 e-3         
neutron mag. mom. to nuclear magneton ratio                 -1.913 042 72            0.000 000 45             
neutron mass                                                1.674 927 351 e-27       0.000 000 074 e-27       kg
neutron mass energy equivalent                              1.505 349 631 e-10       0.000 000 066 e-10       J
neutron mass energy equivalent in MeV                       939.565 379              0.000 021                MeV
neutron mass in u                                           1.008 664 916 00         0.000 000 000 43         u
neutron molar mass                                          1.008 664 916 00 e-3     0.000 000 000 43 e-3     kg mol^-1
neutron-muon mass ratio                                     8.892 484 00             0.000 000 22             
neutron-proton mag. mom. ratio                              -0.684 979 34            0.000 000 16             
neutron-proton mass difference                              2.305 573 92 e-30        0.000 000 76 e-30        
neutron-proton mass difference energy equivalent            2.072 146 50 e-13        0.000 000 68 e-13        
neutron-proton mass difference energy equivalent in MeV     1.293 332 17             0.000 000 42             
neutron-proton mass difference in u                         0.001 388 449 19         0.000 000 000 45         
neutron-proton mass ratio                                   1.001 378 419 17         0.000 000 000 45         
neutron-tau mass ratio                                      0.528 790                0.000 048                
neutron to shielded proton mag. mom. ratio                  -0.684 996 94            0.000 000 16             
Newtonian constant of gravitation                           6.673 84 e-11            0.000 80 e-11            m^3 kg^-1 s^-2
Newtonian constant of gravitation over h-bar c              6.708 37 e-39            0.000 80 e-39            (GeV/c^2)^-2
nuclear magneton                                            5.050 783 53 e-27        0.000 000 11 e-27        J T^-1
nuclear magneton in eV/T                                    3.152 451 2605 e-8       0.000 000 0022 e-8       eV T^-1
nuclear magneton in inverse meters per tesla                2.542 623 527 e-2        0.000 000 056 e-2        m^-1 T^-1
nuclear magneton in K/T                                     3.658 2682 e-4           0.000 0033 e-4           K T^-1
nuclear magneton in MHz/T                                   7.622 593 57             0.000 000 17             MHz T^-1
Planck constant                                             6.626 069 57 e-34        0.000 000 29 e-34        J s
Planck constant in eV s                                     4.135 667 516 e-15       0.000 000 091 e-15       eV s
Planck constant over 2 pi                                   1.054 571 726 e-34       0.000 000 047 e-34       J s
Planck constant over 2 pi in eV s                           6.582 119 28 e-16        0.000 000 15 e-16        eV s
Planck constant over 2 pi times c in MeV fm                 197.326 9718             0.000 0044               MeV fm
Planck length                                               1.616 199 e-35           0.000 097 e-35           m
Planck mass                                                 2.176 51 e-8             0.000 13 e-8             kg
Planck mass energy equivalent in GeV                        1.220 932 e19            0.000 073 e19            GeV
Planck temperature                                          1.416 833 e32            0.000 085 e32            K
Planck time                                                 5.391 06 e-44            0.000 32 e-44            s
proton charge to mass quotient                              9.578 833 58 e7          0.000 000 21 e7          C kg^-1
proton Compton wavelength                                   1.321 409 856 23 e-15    0.000 000 000 94 e-15    m
proton Compton wavelength over 2 pi                         0.210 308 910 47 e-15    0.000 000 000 15 e-15    m
proton-electron mass ratio                                  1836.152 672 45          0.000 000 75             
proton g factor                                             5.585 694 713            0.000 000 046            
proton gyromag. ratio                                       2.675 222 005 e8         0.000 000 063 e8         s^-1 T^-1
proton gyromag. ratio over 2 pi                             42.577 4806              0.000 0010               MHz T^-1
proton mag. mom.                                            1.410 606 743 e-26       0.000 000 033 e-26       J T^-1
proton mag. mom. to Bohr magneton ratio                     1.521 032 210 e-3        0.000 000 012 e-3        
proton mag. mom. to nuclear magneton ratio                  2.792 847 356            0.000 000 023            
proton mag. shielding correction                            25.694 e-6               0.014 e-6                
proton mass                                                 1.672 621 777 e-27       0.000 000 074 e-27       kg
proton mass energy equivalent                               1.503 277 484 e-10       0.000 000 066 e-10       J
proton mass energy equivalent in MeV                        938.272 046              0.000 021                MeV
proton mass in u                                            1.007 276 466 812        0.000 000 000 090        u
proton molar mass                                           1.007 276 466 812 e-3    0.000 000 000 090 e-3    kg mol^-1
proton-muon mass ratio                                      8.880 243 31             0.000 000 22             
proton-neutron mag. mom. ratio                              -1.459 898 06            0.000 000 34             
proton-neutron mass ratio                                   0.998 623 478 26         0.000 000 000 45         
proton rms charge radius                                    0.8775 e-15              0.0051 e-15              m
proton-tau mass ratio                                       0.528 063                0.000 048                
quantum of circulation                                      3.636 947 5520 e-4       0.000 000 0024 e-4       m^2 s^-1
quantum of circulation times 2                              7.273 895 1040 e-4       0.000 000 0047 e-4       m^2 s^-1
Rydberg constant                                            10 973 731.568 539       0.000 055                m^-1
Rydberg constant times c in Hz                              3.289 841 960 364 e15    0.000 000 000 017 e15    Hz
Rydberg constant times hc in eV                             13.605 692 53            0.000 000 30             eV
Rydberg constant times hc in J                              2.179 872 171 e-18       0.000 000 096 e-18       J
Sackur-Tetrode constant (1 K, 100 kPa)                      -1.151 7078              0.000 0023               
Sackur-Tetrode constant (1 K, 101.325 kPa)                  -1.164 8708              0.000 0023               
second radiation constant                                   1.438 7770 e-2           0.000 0013 e-2           m K
shielded helion gyromag. ratio                              2.037 894 659 e8         0.000 000 051 e8         s^-1 T^-1
shielded helion gyromag. ratio over 2 pi                    32.434 100 84            0.000 000 81             MHz T^-1
shielded helion mag. mom.                                   -1.074 553 044 e-26      0.000 000 027 e-26       J T^-1
shielded helion mag. mom. to Bohr magneton ratio            -1.158 671 471 e-3       0.000 000 014 e-3        
shielded helion mag. mom. to nuclear magneton ratio         -2.127 497 718           0.000 000 025            
shielded helion to proton mag. mom. ratio                   -0.761 766 558           0.000 000 011            
shielded helion to shielded proton mag. mom. ratio          -0.761 786 1313          0.000 000 0033           
shielded proton gyromag. ratio                              2.675 153 268 e8         0.000 000 066 e8         s^-1 T^-1
shielded proton gyromag. ratio over 2 pi                    42.576 3866              0.000 0010               MHz T^-1
shielded proton mag. mom.                                   1.410 570 499 e-26       0.000 000 035 e-26       J T^-1
shielded proton mag. mom. to Bohr magneton ratio            1.520 993 128 e-3        0.000 000 017 e-3        
shielded proton mag. mom. to nuclear magneton ratio         2.792 775 598            0.000 000 030            
speed of light in vacuum                                    299 792 458              (exact)                  m s^-1
standard acceleration of gravity                            9.806 65                 (exact)                  m s^-2
standard atmosphere                                         101 325                  (exact)                  Pa
standard-state pressure                                     100 000                  (exact)                  Pa
Stefan-Boltzmann constant                                   5.670 373 e-8            0.000 021 e-8            W m^-2 K^-4
tau Compton wavelength                                      0.697 787 e-15           0.000 063 e-15           m
tau Compton wavelength over 2 pi                            0.111 056 e-15           0.000 010 e-15           m
tau-electron mass ratio                                     3477.15                  0.31                     
tau mass                                                    3.167 47 e-27            0.000 29 e-27            kg
tau mass energy equivalent                                  2.846 78 e-10            0.000 26 e-10            J
tau mass energy equivalent in MeV                           1776.82                  0.16                     MeV
tau mass in u                                               1.907 49                 0.000 17                 u
tau molar mass                                              1.907 49 e-3             0.000 17 e-3             kg mol^-1
tau-muon mass ratio                                         16.8167                  0.0015                   
tau-neutron mass ratio                                      1.891 11                 0.000 17                 
tau-proton mass ratio                                       1.893 72                 0.000 17                 
Thomson cross section                                       0.665 245 8734 e-28      0.000 000 0013 e-28      m^2
triton-electron mass ratio                                  5496.921 5267            0.000 0050               
triton g factor                                             5.957 924 896            0.000 000 076            
triton mag. mom.                                            1.504 609 447 e-26       0.000 000 038 e-26       J T^-1
triton mag. mom. to Bohr magneton ratio                     1.622 393 657 e-3        0.000 000 021 e-3        
triton mag. mom. to nuclear magneton ratio                  2.978 962 448            0.000 000 038            
triton mass                                                 5.007 356 30 e-27        0.000 000 22 e-27        kg
triton mass energy equivalent                               4.500 387 41 e-10        0.000 000 20 e-10        J
triton mass energy equivalent in MeV                        2808.921 005             0.000 062                MeV
triton mass in u                                            3.015 500 7134           0.000 000 0025           u
triton molar mass                                           3.015 500 7134 e-3       0.000 000 0025 e-3       kg mol^-1
triton-proton mass ratio                                    2.993 717 0308           0.000 000 0025           
unified atomic mass unit                                    1.660 538 921 e-27       0.000 000 073 e-27       kg
von Klitzing constant                                       25 812.807 4434          0.000 0084               ohm
weak mixing angle                                           0.2223                   0.0021                   
Wien frequency displacement law constant                    5.878 9254 e10           0.000 0053 e10           Hz K^-1
Wien wavelength displacement law constant                   2.897 7721 e-3           0.000 0026 e-3           m K

 

Periodic Table of Chemical Elements

Explore key information about the chemical elements through this periodic table
Group 1 2   3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Period  
1
1
H
1.008
 
2
4.0026
2
3
6.94
4
9.0122
 
5
B
10.81
6
C
12.011
7
N
14.007
8
O
15.999
9
F
18.998
10
20.180
3
11
22.990
12
24.305
 
13
26.982
14
28.085
15
P
30.974
16
S
32.06
17
35.45
18
39.948
4
19
K
39.098
20
40.078
 
21
44.956
22
47.867
23
V
50.942
24
51.996
25
54.938
26
55.845
27
58.933
28
58.693
29
63.546
30
65.38
31
69.723
32
72.63
33
74.922
34
78.96
35
79.904
36
83.798
5
37
85.468
38
87.62
 
39
Y
88.906
40
91.224
41
92.906
42
95.96
43
[97.91]
44
101.07
45
102.91
46
106.42
47
107.87
48
112.41
49
114.82
50
118.71
51
121.76
52
127.60
53
I
126.90
54
131.29
6
55
132.91
56
137.33
*
71
174.97
72
178.49
73
180.95
74
W
183.84
75
186.21
76
190.23
77
192.22
78
195.08
79
196.97
80
200.59
81
204.38
82
207.2
83
208.98
84
[208.98]
85
[209.99]
86
[222.02]
7
87
[223.02]
88
[226.03]
**
103
[262.11]
104
[265.12]
105
[268.13]
106
[271.13]
107
[270]
108
[277.15]
109
[276.15]
110
[281.16]
111
[280.16]
112
[285.17]
113
[284.18]
114
[289.19]
115
[288.19]
116
[293]
117
[294]
118
[294]
   
*Lanthanoids *
57
138.91
58
140.12
59
140.91
60
144.24
61
[144.91]
62
150.36
63
151.96
64
157.25
65
158.93
66
162.50
67
164.93
68
167.26
69
168.93
70
173.05
 
**Actinoids **
89
[227.03]
90
232.04
91
231.04
92
U
238.03
93
[237.05]
94
[244.06]
95
[243.06]
96
[247.07]
97
[247.07]
98
[251.08]
99
[252.08]
100
[257.10]
101
[258.10]
102
[259.10]
 

 

Periodic Table of Elements

Periodic Table of Elements

A Resource for Elementary, Middle School, and High School Students

Group 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Period
1 1H

1.008

2He

4.003

2 3Li

6.94

4Be

9.012

5B

10.81

6C

12.01

7N

14.01

8O

16.00

9F

19.00

10Ne

20.18

3 11Na

22.99

12Mg

24.31

13Al

26.98

14Si

28.09

15P

30.97

16S

32.06

17Cl

35.45

18Ar

39.95

4 19K

39.10

20Ca

40.08

21Sc

44.96

22Ti

47.88

23V

50.94

24Cr

52.00

25Mn

54.94

26Fe

55.85

27Co

58.93

28Ni

58.69

29Cu

63.55

30Zn

65.39

31Ga

69.72

32Ge

72.64

33As

74.92

34Se

78.96

35Br

79.90

36Kr

83.79

5 37Rb

85.47

38Sr

87.62

39Y

88.92

40Zr

91.22

41Nb

92.91

42Mo

95.96

43Tc

(98)

44Ru

101.1

45Rh

102.9

46Pd

106.4

47Ag

107.9

48Cd

112.4

49In

114.8

50Sn

118.7

51Sb

121.8

52Te

127.6

53I

126.9

54Xe

131.3

6 55Cs

132.9

56Ba

137.3

* 72Hf

178.5

73Ta

180.9

74W

183.9

75Re

186.2

76Os

190.2

77Ir

192.2

78Pt

195.1

79Au

197.0

80Hg

200.5

81TI

204.38

82Pb

207.2

83Bi

209.0

84Po

(209)

85At

(210)

86Rn

(222)

7 87Fr

(223)

88Ra

(226)

** 104Rf

(265)

105Db

(268)

106Sg

(271)

107Bh

(270)

108Hs

(277)

109Mt

(276)

110Ds

(281)

111Rg

(280)

112Cn

(285)

113Uut

(284)

114Fl

(289)

115Uup

(288)

116Lv

(293)

117Uus

(294)

118Uuo

(294)

Lanthanide Series* 57La

138.9

58Ce

140.1

59Pr

140.9

60Nd

144.2

61Pm

(145)

62Sm

150.4

63Eu

152.0

64Gd

157.2

65Tb

158.9

66Dy

162.5

67Ho

164.9

68Er

167.3

69Tm

168.9

70Yb

173.0

71Lu

175.0

Actinide Series** 89Ac

(227)

90Th

232

91Pa

231

92U

238

93Np

(237)

94Pu

(244)

95Am

(243)

96Cm

(247)

97Bk

(247)

98Cf

(251)

99Es

(252)

100Fm

(257)

101Md

(258)

102No

(259)

103Lr

(262)

Alkali metals Lanthanides
Alkaline earth metals Actinides
Transition metals Nonmetals
Post-transition metals Halogens
Metalloid Noble gases

 

Element number 114: flerovium (symbol Fl) and element number 116: livermorium (symbol Lv)

The International Union of Pure and Applied Chemistry (IUPAC) has recommended names for elements 114 and 116. Scientists from the Lawrence Livermore National Laboratory (LLNL) and at Dubna proposed the names as Flerovium for element 114 and Livermorium for element 116.

Flerovium (atomic symbol Fl) was chosen to honor Flerov Laboratory of Nuclear Reactions, where superheavy elements, including element 114, were synthesized. Georgiy N. Flerov (1913-1990) was a renowned physicist who discovered the spontaneous fission of uranium and was a pioneer in heavy-ion physics. He is the founder of the Joint Institute for Nuclear Research. In 1991, the laboratory was named after Flerov – Flerov Laboratory of Nuclear Reactions (FLNR).

Livermorium (atomic symbol Lv) was chosen to honor Lawrence Livermore National Laboratory (LLNL) and the city of Livermore, Calif. A group of researchers from the Laboratory, along with scientists at the Flerov Laboratory of Nuclear Reactions, participated in the work carried out in Dubna on the synthesis of superheavy elements, including element 116. (Lawrencium — Element 103 — was already named for LLNL’s founder E.O. Lawrence.)

In 1989, Flerov and Ken Hulet (1926-2010) of LLNL established collaboration between scientists at LLNL and scientists at FLNR; one of the results of this long-standing collaboration was the synthesis of elements 114 and 116.

The creation of elements 116 and 114 involved smashing calcium ions (with 20 protons each) into a curium target (96 protons) to create element 116. Element 116 decayed almost immediately into element 114. The scientists also created element 114 separately by replacing curium with a plutonium target (94 protons).

The creation of elements 114 and 116 generate hope that the team is on its way to the “island of stability,” an area of the periodic table in which new heavy elements would be stable or last long enough for applications to be found.

The new names were submitted to the IUPAC in late October. The new names will not be official until about five months from now when the public comment period is over.

Search for element 113 concluded at last?

Press release from RIKEN Nishina Center for Accelerator-Based Science

The most unambiguous data to date on the elusive 113th atomic element has been obtained by researchers at the RIKEN Nishina Center for Accelerator-based Science (RNC). A chain of six consecutive alpha decays, produced in experiments at the RIKEN Radioisotope Beam Factory (RIBF), conclusively identifies the element through connections to well-known daughter nuclides. The groundbreaking result, reported in the Journal of Physical Society of Japan, sets the stage for Japan to claim naming rights for the element.

Steps in chain of decays from element 113 to mendelevium-254
The search for superheavy elements is a difficult and painstaking process. Such elements do not occur in nature and must be produced through experiments involving nuclear reactors or particle accelerators, via processes of nuclear fusion or neutron absorption. Since the first such element was discovered in 1940, the United States, Russia and Germany have competed to synthesize more of them. Elements 93 to 103 were discovered by the Americans, elements 104 to 106 by the Russians and the Americans, elements 107 to 112 by the Germans, and the two most recently named elements, 114 and 116, by cooperative work of the Russians and Americans.

With their latest findings, associate chief scientist Kosuke Morita and his team at the RNC are set follow in these footsteps and make Japan the first country in Asia to name an atomic element. For many years Morita’s team has conducted experiments at the RIKEN Linear Accelerator Facility in Wako, near Tokyo, in search of the element, using a custom-built gas-filled recoil ion separator (GARIS) coupled to a position-sensitive semiconductor detector to identify reaction products. On August 12th those experiments bore fruit: zinc ions travelling at 10% the speed of light collided with a thin bismuth layer to produce a very heavy ion followed by a chain of six consecutive alpha decays identified as products of an isotope of the 113th element (Figure 1).

While the team also detected element 113 in experiments conducted in 2004 and 2005, earlier results identified only four decay events followed by the spontaneous fission of dubnium-262 (element 105). In addition to spontaneous fission, the isotope dubnium-262 is known to also decay via alpha decay, but this was not observed, and naming rights were not granted since the final products were not well known nuclides at the time. The decay chain detected in the latest experiments, however, takes the alternative alpha decay route, with data indicating that Dubnium decayed into lawrencium-258 (element 103) and finally into mendelevium-254 (element 101). The decay of dubnium-262 to lawrencium-258 is well known and provides unambiguous proof that element 113 is the origin of the chain.

Combined with their earlier experimental results, the team’s groundbreaking discovery of the six-step alpha decay chain promises to clinch their claim to naming rights for the 113th element.

“For over 9 years, we have been searching for data conclusively identifying element 113, and now that at last we have it, it feels like a great weight has been lifted from our shoulders,” Morita said. “I would like to thank all the researchers and staff involved in this momentous result, who persevered with the belief that one day, 113 would be ours. For our next challenge, we look to the uncharted territory of element 119 and beyond.”

Printable Periodic Table

This item contains links to two “portable document format” (pdf) files that you can download, read, and print with the Adobe Acrobat Reader on whatever computer you use. You can use this file to print copies of the periodic table for yourself, groups of students, whatever. What you may not do is sell it, or distribute it on media which you sell. If you are connected to the InterNet and your Adobe Acrobat software is sufficiently current, click on any of the elements in the periodic table from within the Adobe Acrobat reader program to retrieve information about that element from the WebElements site.

The 5-figure version is called periodic_table_5sf_2013-08-29_NoRestriction.pdf. This version is appropriate for most uses, in particular for school use and many university requirements. It lists the atomic weights to 5 significant figures, all that is needed for many purposes.

The full version is called periodic_table_full_2013-08-29_NoRestriction.pdf. This version is appropriate if you want the atomic weights to have the maximum number of figures. The estimated errors as given by IUPAC are also included. This will suit the professional in particular but is also suitable in many cases for school and university requirements.

These files were updated 07 June 2012 to include the latest IUPAC values.

Attachment Size
periodic_table_5sf_2013-08-29_NoRestriction.pdf 565.675 KB
periodic_table_full_2013-08-29_NoRestriction.pdf 785.407 KB

Tantalising news about element 117

Notes from the 31st meeting of PAC for Nuclear Physics seems to suggest that a claim for element 117 (at the base of the halogen column) may come in the coming weeks and months. It’s not very clear which isotopes may have been formed so watch this space.

IV. Experiments on the synthesis of element 117
The PAC heard with great interest the report on the results of the experiment dedicated to the synthesis of element 117 in the 48Ca + 249Bk reaction. The PAC congratulates the staff of the Flerov Laboratory on the discovery of element 117 and new isotopes of elements 115, 113, 111, 109, 107, and 105. The discovery of chains of two neighboring isotopes emphasizes the importance of the odd-even and odd-odd effect for such heavy nuclei. It is in fact especially interesting that the odd-odd chain (3n channel) neighboring to the odd-even chain (4n channel) is twice longer (6 α particles).

Synthesis of a new element with atomic number Z=117

A paper has just been accepted (5 April 2010) for publication in Physical Review Letters.

International team discovers element 117

A new chemical element has been added to the Periodic Table: A paper on the discovery of element 117 has been accepted for publication in Physical Review Letters.

Oak Ridge National Laboratory is part of a team that includes the Joint Institute of Nuclear Research (Dubna, Russia), the Research Institute for Advanced Reactors (Dimitrovgrad), Lawrence Livermore National Laboratory, Vanderbilt University and the University of Nevada Las Vegas. ORNL’s role included production of the berkelium-249 isotope necessary for the target, which was subjected to an extended, months-long run at the heavy ion accelerator facility at Dubna, Russia.

“Without the berkelium target, there could have been no experiment,” says ORNL Director of Strategic Capabilities Jim Roberto, who is a principal author on the PRL paper and who helped initiate the experiment. The berkelium was produced at the High Flux Isotope Reactor and processed at the adjoining Radiochemical Engineering & Development Laboratory as part of the most recent campaign to produce californium-252, a radioisotope widely used in industry and medicine.

“Russia had proposed this experiment in 2004, but since we had no californium production at the time, we couldn’t supply the berkelium. With the initiation of californium production in 2008, we were able to implement a collaboration,” Roberto says.
Professor Joe Hamilton of Vanderbilt University (who helped establish the Joint Institute for Heavy Ion Research at ORNL) introduced Roberto to Yuri Oganessian of Russia’s JINR. Five months of the Dubna JINR U400 accelerator’s calcium-48 beam – one of the world’s most powerful – was dedicated to the project.

The massive effort identified a total of six atoms of element 117 and the critical reams of data that substantiate their existence.
The two-year experimental campaign began with a 250-day irradiation in HFIR, producing 22 milligrams of berkelium-249, which has a 320-day half-life. The irradiation was followed by 90 days of processing at REDC to separate and purify the berkelium. The Bk-249 target was prepared at Dimitrovgrad and then bombarded for 150 days at the Dubna facility. Lawrence Livermore, which now has been involved in the discovery of six elements with Dubna (113, 114, 115, 116, 117, and 118), contributed data analysis, and the entire team was involved in the assessment of the results.

This is the second element that ORNL has had a role in discovering, joining element 61, promethium, which was discovered at the Graphite Reactor during the Manhattan project and reported in 1946. ORNL, by way of its production of radioisotopes for research, has contributed to the discovery of a total of seven new elements.

Members of the ORNL team include the Physics Division’s Krzysztof Rykaczewsi, Porter Bailey of the Nonreactor Nuclear Facilities Division, and Dennis Benker, Julie Ezold, Curtis Porter and Frank Riley of the Nuclear S&T Division. Roberto says the success of the element-117 campaign underscores the value of international collaborations in science.
“This use of ORNL isotopes and Russian accelerators is a tremendous example of the value of working together,” he says. “The 117 experiment paired one of the world’s leading research reactors–capable of producing the berkelium target material–with the exceptional heavy ion accelerator and detection capabilities at Dubna.”

Islands of Stability

Roberto also says the experiment, in addition to discovering a new chemical element, has pushed the Periodic Table further into the neutron-rich regime for heaviest elements. “New isotopes observed in these experiments continue a trend toward higher lifetimes for increased neutron numbers, providing evidence for the proposed “island of stability” for super-heavy nuclei,” he says. “Because the half-lives are getting longer, there is potential to study the chemistry of these nuclei,” Roberto says. “These experiments and discoveries essentially open new frontiers of chemistry.”

—Bill Cabage

The news about the claim was announced in a press release from the Oak Ridge National Laboratory.