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Laboratory for Radiochemistry and Environmental Chemistry

Mendeleev’s principle against Einsteins relativity news from the chemistry of superheavy elements H.W. Gäggeler. Reminiscences: from Mendelejeev’s periodic table to the discovery of mendelevium, the last “real” chemical element

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Laboratory for Radiochemistry and Environmental Chemistry

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  1. Mendeleev’s principle against Einsteins relativitynews from the chemistry of superheavy elementsH.W. Gäggeler Reminiscences: from Mendelejeev’s periodic table to the discovery of mendelevium, the last “real” chemical element Positioning four new chemical elements into the periodic table during the last decade. Mendelejeevs dreams become true! How reliable is single atom chemistry? Proof of principle with elements Hs and 112 Einsteins influence on the chemistry of heaviest elemenst, so far up to Z=114 Laboratory for Radiochemistry and Environmental Chemistry

  2. Mendelejeev‘s „second“ Periodic Table from 1871 D.I. Mendeleev (8 Feb. 1834 – 2 Feb. 1907)

  3. Predictions by Mendeleev in 1871 • Eka-Al: Discovered by P.E. Lecoq de Boisbaudran in 1875, named Ga • Eka-B: Discovered by L.F. Nilson in 1879, named Sc • Eka-Si: Discovered by C. Winkler in 18886, named Ge

  4. Major refinements • Noble gases: Sir William Ramsey (1894) • Henry Moseley: Atomic number, determined via X-rays, defines ordering of elements (1914) • Glenn T. Seaborg: Actinides series (1945)

  5. Periodic Table in the 1930‘s G.T. Seaborg, W. D. Loveland (1990)

  6. 108 112 106 107 - - Hs Sg Bh 109 Mt 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Periodic Table today 1 18 1 2 H 2 13 14 15 16 17 He 3 4 5 6 7 8 9 10 Li Be B C N O F Ne 11 12 13 14 15 16 17 18 Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S Cl Ar 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 55 56 57-71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 87 88 104 105 89-103 114 Fr Ra Ac Rf Db 110 111 114 116 113 115 116 118 Rg Ds Lanthanides Actinides

  7. Courtesy: Yu.Ts. Oganessian

  8. Discovery of new elements – the failure of chemistry! • The heaviest element discovered purely by chemical means: Mendelevium! (1955)→ Synthesis: bombardment of 253Es with a-particles.→ Collection of products in a foil. → Separation of products after dissolution of foil on a cation exchange column with a-HIB

  9. Elution of actinides on a cation exchange column by a-HIB Count rate [cpm] Elution in drops

  10. Discovery of Mendelevium on the basis of 7 atoms unknown Cf Es Fm A. Ghiorso et al., Phys. Rev. 98, 1518 (1955)

  11. 108 112 106 107 - - Hs Sg Bh 108 109 112 107 - - Mt Hs Bh 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Positioning of new elements during the last decade 1 18 1 2 H 2 13 14 15 16 17 He 2009? 2002 2007 1999 3 4 5 6 7 8 9 10 Li Be B C N O F Ne 11 12 13 14 15 16 17 18 Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S Cl Ar 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 55 56 57-71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 87 88 104 105 89-103 114 Fr Ra Ac Rf Db 110 111 114 116 Rg - - Ds Lanthanides Actinides Techniques developed at PSI and Bern University

  12. Reactions used and number of atoms found in the „first ever chemical studies“ during the last decade • Bohrium (Z=107); Main experiments at PSI249Bk(22Ne;4n)267Bh (T1/2 = 17 s); 6 atoms (R. Eichler et al., Nature, 407, 64 (2000)) • Hassium (Z=108); Main experiments at GSI248Cm(26Mg;5n)269Hs(T1/2 = 15 s); 7 atoms (C.E. Düllmann et al., Nature, 418, 860 (2002)) • Element 112; Main experiments at FLNR/JINR242Pu(48Ca,3n)287114 (T1/2 = 0.5 s)283112 (T1/2 = 4 s); 2 atoms (R. Eichler et al., Nature, 447, 72 (2007)). Confirmed with 3 additional atoms (R. Eichler et al., Angew. Chem. Int. Ed., 47(17), 3262 (2008) • Element 114: Main experiments at FLNR/JINR242,244Pu(48Ca;3,4n)287,288,289114 (T1/2 = 0.5s;0.8s;2.6s); 3 – 4 atoms (R. Eichler et al.,submitted to Nature (2008)).

  13. How reliable is single atom chemistry?1st example: hassium chemistry • Investigation of hassium in form of its very volatile molecule HsO4 • Applied technique: Thermochromatography

  14. T yield length Thermochromatography Internal chromatogram Temperature gradient T=300K T=100K Tdep detectors Result:Tdep DHads

  15. Thermochromatography of OsO4 and HsO4 90 0 Exp:269Hs (T1/2 =9.7 s) -44±5 °C -20 80 Exp: 172Os(T1/2=19.2 s) MCS (Os): -39.5 kJ/mol -40 70 4 atoms MCS (Hs): -46.5 kJ/mol HsO4 -82±5 °C -60 Temperature profile 60 OsO4 -80 50 Rel. Yield [%] -100 1 atom 2 atoms Temperature [°C] 40 -120 30 -140 20 -160 10 -180 0 -200 1 2 3 4 5 6 7 8 9 10 11 12 Detector C.E. Düllmann et al., Nature 418,860 (2002)

  16. Nobel Laureate Glenn T. Seaborg, The first human being, able to celebrate „his“ element!

  17. How reliable is single atom chemistry?2nd example: element 112 • Element 112 presumably is highly volatile so that it can be separated and analysed in elemental form • Applied technique: Thermochromatography

  18. 108 112 106 107 - - Hs Sg Bh 109 Mt 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Periodic Table today 1 18 1 2 H 2 13 14 15 16 17 He 3 4 5 6 7 8 9 10 Li Be B C N O F Ne 11 12 13 14 15 16 17 18 Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S Cl Ar 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 55 56 57-71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 87 88 104 105 89-103 114 Fr Ra Ac Rf Db 110 111 114 116 113 115 116 118 Rg Ds Lanthanides Actinides

  19. Trend of sublimation enthalpy within group 12 ? Mendeleev says: 112 an even more volatile metal compared to Hg!

  20. Pitzer (1975) says: because of relativistic effects element 112 could well behave like a noble gas. Reason: E112 has a filled 6d107s2 electronic shell configuration However,…..

  21. Relativistic effects • High atomic number: strong Coulomb attraction causes electrons to move faster. • Causes relativistic mass increase [m=m0(1-b2)], with b=v/c; and, as a consequence, contraction of spherical orbitals (ns, np1/2) • Energy levels of spherical orbitals are increased • Energy levels of high angular momentum orbitals are destabilized due to shielding effects by spherical orbitals • Strong spin-orbit splitting

  22. Courtesy:P. Schwerdtfeger Example: the relativistic 6s/7s contraction in Au and Rg Consequence:Cu, Ag, Au nd10(n+1)s1 Zn+,Cd+,Hg+ however: Rg, 112+ nd9(n+1)s2 (2D5/2) E.Eliav, U.Kaldor, P.Schwerdtfeger, B.Hess, Y.Ishikawa, Phys. Rev. Lett.73, 3203 (1994). M.Seth, P.Schwerdtfeger, M.Dolg, K.Faegri, B.A.Hess, U.Kaldor, Chem. Phys. Lett.250, 461 (1996).

  23. Relativistic Effects P. Pyykkö direct effect (contraction) indirect effect (expansion) relativistic M.Kaupp, Spektrum der Wissenschaften, 2005 nonrelativistic

  24. How to experimentally determine a metallic character of a volatile element at a single atom level? → Determine interaction energy (adsorption enthalpy) with noble metals (e.g. Au) → If metallic: strong interaction (adsorption enthalpy) if non-metallic (noble gas like): weak interaction

  25. Metal Surface

  26. Quartz Surface Tdep. Tl, Po, Pb, Bi ≥ 500 K

  27. The EPIPHANIOMETER (Teflon) for 211Pb (via 211Bi) 219Rn 211Pb No 211Pb detected for clean gas (no aerosol particles) H.W. Gäggeler et al., J. Aerosol Sci., 20, 557 (1989)

  28. Application to atmospheric aerosol detection at exotic sites

  29. The element 112,114 experiments (IVO Technique) Beam (48Ca) Teflon capillary Window/ Target (242,244Pu) Cryo On-line Detector (4p COLD) SiO2-Filter Ta metal 850°C (32 pairs PIN diodes, one side gold covered) 112,114? Loop Rn Hg Quartz inlay Recoil chamber Temperature gradient: 35°C to – 180 °C Quartz column Beam stop T Carrier gas He/Ar (70/30) l

  30. Reported at FLNR: Oganessian et al. 2004 291116 6.3 ms 10.7 MeV 287114 0.51 s 10.02 MeV 283112 9.38 MeV 283112 9.47 MeV 283112 9.52 MeV 283112 9.35 MeV 283112 9.52 MeV 283112 4 s 9.54 MeV 279Ds t: 0.592 s SF 108+123 MeV 279Ds t: 0.536 s SF 127+105 MeV 279Ds t: 0.072 s SF 112+n.d. MeV 279Ds t: 0.773 s SF 85+12 MeV 279Ds t: 0.088 s SF 94+51 MeV 279Ds 0.18 s SF(>90%) 205 MeV NR <1E-5 NR =0.05 The E112 experiments in 2006/2007 Observed in Chemistry: 242Pu (48Ca, 3n) 287114 6.2•101848Ca during eff. 32 days (8 weeks absolute)

  31. Results (-28°C) (-5°C) (-21°C) (-39°C) (-124°C) Monte Carlo simulation for one single component Experiment -52+4-3 kJ/mol gas flow Courtesy: R. Eichler

  32. Trend of sublimation enthalpy within group 12

  33. 289114 2.6 s 9.82 MeV 287114 0.51 s 10.02 MeV 288114 0.8 s 9.95 MeV 285112 29 s 9.16 MeV 283112 4 s 9.54 MeV 284112 0.097 s SF 281Ds 11 s SF 279Ds 0.2 s SF Production of E114 244Pu (48Ca, 3-4n) 288-289114 242Pu (48Ca, 3n) 287114 Yu.Ts. Oganessian et al., 2004

  34. 120 100 Standard enthalpies of gaseous monoatomic elements 80 DH°298 [kcal/mol] 60 40 20 0 100 120 60 80 40 20 0 Atomic number Extrapolation of the standard enthalpies for SHE B. Eichler, 1974

  35. 289114 287114 10.04 MeV 288114 9.81 MeV 288114 9.95 MeV 285112 9.20 MeV 283112 t: 10.93 s a 9.53 284112 t: 0.11 s SF 62+n.d. 284112 t: 0.10 s SF 108+n.d. 279Ds t: 0.242 s SF 114+103 281Ds t: 3.38 s SF 106+44 Results with element 114 Dubna 2007 - 2008 244Pu (48Ca, 3-4n) 288-289114 242Pu (48Ca, 3n) 287114 3.1•101848Ca during 16 days 1.43•101948Ca during 51 days Det#4 NR=1.5E-3 Det#6 NR=2E-2 NR=1.1E-2 NR=1.8E-3

  36. ice gold -88°C -4°C -90°C -93°C Results (2007/2008) Z=112

  37. Prediction and exp. result Dubna 2007/2008 B. Eichler 2003 R. Eichler et al. 2002 V.Pershina et al 2008 114Exp(2007/2008) Strong stabilization of elemental 6d107s27p1/22 atomic state!

  38. How to interpret low adsorption enthalpy of E114? Unexpected observation: E114 significantly different to Pb and even more volatile than E112.

  39. Calculated van der Waals energies using covalent radii1, polarizabilities2 and ionisation potentials2 1P.Pyykkö, M. Atsumi, Chem.Eur. J., 2009, 15, 186 2E=114: C. Thierfelder, B. Assadollahzadeh, P. Schwerdtfeger, S. Schäfer, R. Schäfer, Phys. Rev. A 78, 052506 (2008)E=112: V.Pershina, A. Borschevsky, E. Eliav, U. Kaldor, J. Chem. Phys. 128, 024707 (2008) E112 on Au: -30 kJ/Mol; exp.: -52 kJ/MolE114 on Au: -23 kJ/Mol; exp.: -34 kJ/Mol (Rn on Au: - 24 kJ/Mol; exp.: -27 kJ/Mol) Courtesy: R. Eichler

  40. Conclusion • On-line gas phase chemistry has reached the sensitivity of about 1 pb • Month-long beam times at highest possible beam intensities mandatory for chemical studies • Single atom chemistry yields reliable chemical information • Elements 112 and 114 surprisingly volatile • Next: element 113 (eka-Tl). Expected volatility of At. • Far future: chemistry from actually s-range to ms-range? (e.g. Stern-Gerlach experiment for atomic electronic configuration) [Proposal E.K. Hulet]

  41. Acknowledgement - Excerpt for Z=112/114 studies - PSI team: R. Eichler et al. FLNR chemistry: S. Dmitriev, S. Shishkin FLNR GNS team: V.K. Utyonkov et al. FLNR VASSILISSA team: A.V. Yeremin et al. FLNR support: Yu. Ts. Oganessian LLNR target: K.J.Moody et al.

  42. Adsorption of E112 on Au E112calc -52+4-3 kJ/mol B. Eichler 1985 B. Eichler 2003 V. Pershina et al. 2005/08 R. Eichler et al. 2002 R. Eichler et al. 2002 Eichler, R. et al. Nature 487, 72 (2007) Result can be used to improve the prediction models

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