Chemie radioaktivních prvků část 3 - transaktinoidy J. John Periodic table of the elements 1 IUPAC names 18 1 2 H 2 13 14 15 16 17 He 3 4 5 6 7 8 9 10 Li Be Since 2016 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 89-103 104 105 106 107 108 Fr Ra Ac Rf Db Sg Bh Hs 109 110 111 112 113 114 115 116 117 118 Mt Ds Rg Cn Nh Fl Mc Lv Ts Og 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Lanthanides 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 Actinides Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Superheavy Elemens - Why Study? • Test validity of the Extrapolations of the Periodic Table • Determine the Influence of Relativistic Effects on Chemical Properties • Help to Predict the Chemical Properties of the Heavier Elements • Determine Nuclear Properties of the Heaviest Elements Superheavy Elemens - Stability? island of 114 island of heavy „stability“ nuclides strait peak of U of insta- peak of Pb bility 82 strait of sea of instability radioactivity 50 peak of Sn Number of protons Number 20 peak of Ca sea of instability 20 82 126 184 Number of neutrons SHE - produktion Hot fusion – light projectile on heavy target, e.g. 248Cm + 22Na → 266Sg + 4n Compound nucleus, in this case 270Sg, is highly excited and a certain number of neutrons ”evaporates”. Each of these neutrons takes with it some 10 MeV of energy. Cold fusion – medium weight projectile on lighter target, e.g. 208Pb + 50Ti → 257Rf + n In this case is the compound nuclues not so highly excited and only 0-1 neutrons ”evaporate”. Accelerators – Dubna, Darmstadt, Berkeley and RIKEN Hot fusion with 48Ca ions as projectile allowed to reach the ”island of stability” around Z = 114 and N = 182. (N/Z = 1.6) Superheavy Elemens – Current Status Atomic number Name Chemical symbol 104 rutherfordium Rf 105 dubnium Db 106 seaborgium Sg 107 bohrium Bh 108 hassium Hs 109 meitnerium Mt 110 darmstadtium Ds 111 roentgenium Rg 112 copernicium Cn 113 Nihonium Nh 114 flerovium Fl 115 Moscovium Mc 116 livermorium Lv 117 Tenessine Ts 118 Oganesson Og 104 – Rutherfordium (Rf) 1964: Dubna (Russia), Flerov et al. 242 22 260 SF, 0.3 s Pu( Ne,4n) 104 Kurchatovium (Ku) s 0.2 nb 1 at/5 hr 1969: Berkeley (USA), Ghiorso et al. 249 12,13 257,259 a Cf( C,4n) 104 Rutherfordium (Rf) 257 257 Final determination of Z for 104 – coicidence of KX of No with a from 104 Today: A = 253-262 261 248 18 104 T1/2 = 1.1 min a Cm( O,5n) Chemistry Eka-hafnium. Dubna – volatile chloride (Zvára et al., 1966) (?) Berkeley & Oak Ridge (Silva, 1970): Dowex 50 + a-HiB – behaves like IV, NOT III study performed with 100 atoms of 261Rf SHE – Rf: Target System 104Rf 104 - zařízení 105 – Dubnium (Db) 1968: Dubna (Russia), Flerov et al. 243 22 261 a , 0,1 0.3 s 257 Am( Ne,4n) 105 Lr Ea = 9.4 MeV 243 22 260 a , 0.01 s 256 Am( Ne,5n) 105 Lr Ea = 9.7 MeV Nielsbohrium (Ns) 1970: Berkeley (USA), Ghiorso et al. 249 15 260 a , 1.6 s 256 Cf( N,5n) 105 Lr “Proof“ – coincidence 105 - Lr Hahnium (Ha) 260 Final determination of Z (1977) – coincidence of LX of Lr with a from 105 Today: A = 255-262 262 249 18 Db T1/2 = 34 s 78 % SF, 22 % a Bk( O,5n) Chemistry Dubna – gas chromatography T <50; 350> °C Volatilily of chlorides: HfCl4 < DbClx < NbCl5 Eka-tantalum (Zvára et al., 1970-75) 105 - zařízení 106 – Seaborgium (Sg) Forecast: Eka-tungsten 1974: Berkeley (USA), Ghiorso et al. 249 18 263 a , 0.9 s Cf( O,4n) 106 Ea = 9.06 MeV “Proof“ – correlation of decays 263106 259Rf 255No 1974: Dubna (Russia), Oganesyan et al. 207,208 54 259 SF, ? ms Pb( Cr,2-3n) 106 a SF (probably 260106 256Rf ) Today: A = 259-263 263 249 18 Sg T1/2 = 0.9 s a Cf( O,4n) Chemistry Theoretical forecast: like W or Mo, more complexes Experimental: Atom – at – a - time chemistry member of group 6 of the PTE 104-106 – Chemie 1 104-106 – Chemie 2 104-106 – Chemie 3 Aqueous chemistry with Transactinides 104-106 – Chemie 4 104-106 – Chemie 5 104-106 – Chemie 6 104-106 – Chemie 7 104-106 – Chemie 8 Rf 104-106 – Chemie 9 104-106 – Chemie 10 Db 104-106 – Chemie 11 TiOA = tri-iso-octyl amine104 -106 – Chemie 12 Diluent: toluene 104-106 – Chemie 13 Sg 104-106 – Chemie 14 104-106 – Chemie 15 SHE homologues synthesis and gas-jet transport at U-120M accelerator in Řež Experimental set-up – Řež Target chamber at cyclotrone U-120 Cyclotron beam: 100-500 nA 3He2+ @ 47 MeV Target holder Faraday cup at the beam stop Gas jet Experimental set-up – Řež Target activity check Removing the catcher foil Experimental set-up – Řež Aerosol: KCl cluster source – oven 620-680°C Gas jet: He at 2 bar, 0.5 - 4 L/min Catcher filters Pressure and gas Oven with KCl flow control Temperature control 107 – Bohrium (Bh) Forecast: Eka-rhenium 1976: Dubna (Russia), Oganesyan et al. 209 54 261 20 % SF, 2 ms; 80 % a 257 SF, 5 s Bi( Cr,2n) 107 Db 1981: GSI Darmstadt (Germany), Münzenberg, Armbruster et al. 209 54 262 a , 4.7 ms 258 a 254 a 250 Bi( Cr,n) 107 Db Lr Fm Position-sensitive SSB detectors – implantation Proof: Whole decay chain in one pixel 6 atoms prepared 107 - zařízení Gas Phase Chemistry with Transactinides Gas Phase Chemistry Community: Isothermal Chromatography: Gas flow C] ° T 50% tRet. = T1/2 Yield [%] Yield Temperature [ Temperature Column length [cm] low Temperature [°C] high Thermochromatography: Ta C] ° Gas flow Yield [%] Yield Temperature [ Temperature Column length [cm] high Temperature [°C] low OLGA a device to measure retention temperatures of volatile species GasGas ChromatographyChromatography:: OLGAOLGA IIIIII Recluster Aerosol Gas-jet (Ar/CsCl) Reactive gas Cl2/SOCl2/O2 He/C-Aerosol Gas-jet Reaction oven Quartz column 1000°C Recluster unit Quartz wool plug Working Hypothesis 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac** Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu * ** Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Working Hypothesis Single atoms require simple stable molecules suitable for gas phase investigations Element Compound Method/surface Bond Character Rf RfOX2, RfX4 TC,IC / quartz Chemisorption Db DbOX3, DbX5 TC,IC / quartz Chemisorption Sg SgO2X2 TC,IC / quartz Chemisorption Bh BhO3X, BhO3OH IC / quartz Chemisorption Hs HsO4 TC / quartz Chemisorption/Physisorption X = halogen Model experiments single atoms of lighter homologues “Microscopic-Macroscopic” Approach of Gas Phase Chemistry Adsorption of single atoms / molecules DHads H ? D subl -DH0(s) -DH0(g) Stability of macroscopic phases “Microscopic-Macroscopic” Approach of Gas Phase Chemistry 300 quartz surface SrCl2 B CaCl 250 2 TbCl 3 BaCl2 AgCl ThCl4 LaCl 200 RbCl LuCl3 3 YbCl3 DbOCl ScCl3 3 PdCl YCl3 InCl3 2 SgO2Cl2 NiCl2 / kJ/mol 150 ScCl AuCl3ZnCl2 3 CoCl ads ZrCl4 2 o HfCl 4 CdCl CsCl H HgCl2BiCl 2 D 3 FeCl PbCl - 100 3 2 SbCl3 NbOCl3 TaOCl3 WO Cl 50 MoO Cl 2 2 TeCl4 2 2 A. Türler et al. 1999 RfCl4 R. Eichler et al. 2000 BhO3Cl 0 0 50 100 150 200 250 300 350 400 o DH subl / kJ/mol Eichler, B. et al.: J. Phys. Chem. A 103(46), 9296 (1999). o o - ΔH ad s 21.5 5.2 0.600 0.025 ΔH su b l “Microscopic-Macroscopic” Approach of Gas Phase Chemistry 500 M oO 2 Cquartz surface 400 IrO 2 R uO M oO 2 3 WO3 300 C rO 3 / kJ/m ol ads H 2WO4 o 200 H H M oO 2 4 TcO D H C rO 3 - 2 4 R eO H 2IrO 4 3 100 HsO4 R uO 4 R uO IrO 3 3 O sO H R eO C.