13701-90-1Relevant articles and documents
Mixed-valence thallium(I,III) bromides the crystal structure of α-Tl2Br3
Ackermann, Rupprecht,Hirschle, Christian,Rotter, Heinz W.,Thiele, Gerhard
, p. 2675 - 2682 (2002)
Thallium sesquibromide Tl2Br3 is dimorphic. Scarlet coloured crystals of α-Tl2Br3 were obtained by reactions of aqueous solutions of TlBr3 and Tl2SO4 in agarose gel. In case of rapid crystallisation of hydrous TlBr3/TlBr solutions and from TlBr/TlBr2 melts β-Tl2Br3 is formed as scarlet coloured, extremely thin lamellae. The crystal structures of both forms are very similar and can be described as mixed-valence thallium(I)-hexabromothallates(III) Tl3 [TlBr6]. In the monoclinic unit cell of α-Tl3[TlBr6] (a = 26.763(7) A; b = 15.311(6) A; c = 27.375(6) A; β = 108.63(2)°, Z = 32, space gr. C2/c) the 32 TlIII-cations are found in strongly distorted octahedral TlBr6 groups. The 96 TlI cations are surrounded either by four or six TlBr6 groups with contacts to 8 or 9 Br neighbors. Crystals of β-Tl3[TlBr6] by contrast show almost hexagonal metrics (a = 13.124(4) A, b = 13.130(4) A, c = 25.550(7) A, γ = 119.91(9)°, Z = 12, P21/m). Refinements of the parameters revealed structural disorder of TlBr6 units, possibly resulting from multiple twinning. Both structures are composed of Tl2[TlBr6]- and Tl4 [TlBr6]+ multilayers, which alternate parallel (001). The structural relationships of the complicated structures of α- and β-Tl3[TlBr6] to the three polymorphous forms of Tl2Cl3 as well as to the structures of monoclinic hexachlorothallates M3TlCl6 (M = K,Rb) and the cubic elpasolites are discussed.
Equilibrium dynamics in the thallium(III)-bromide system in acidic aqueous solution. A205Tl NMR study
Bányai, István,Glaser, Julius
, p. 4703 - 4710 (2007/10/02)
Kinetics of ligand exchange in the thallium(III)-bromide system in aqueous 3 M perchloric acid solution was studied by measuring 205Tl NMR line widths at 25 °C. Three types of parallel second-order reaction paths were found to be dominant. For the reactions TlBrm3-m + *TlBrn3-n ? *TlBrm3-m + TlBrn3-n the rate constants are k01 = 2.8 × 104 (1.25 × 104 at 10 °C), k12 = 7.5 × 104, k23 = 8.2 × 106, and k34 = 2.3 × 107 M-1 s-1. For the reactions Tl3+ + TlBr2+ ? TIBr2+ + TlBr2+ TlBr2+ + TlBr3, ? TlBr2+ + TlBr2+ k02 = 7.1 × 105, k11 = 6.1 × 103, and k13 = 2.4 × 107 M-1 s-1 (k22 = 2.3 × 105 M-1 s-1, calculated by use of equilibrium constants), and for the complex formation (anation) reactions TlBrn3-n + Br- ? TlBrn+12-n k'01 10, k'12 = 5.8 × 109, k'23 = 5.6 × 1010, k'34 = 1.5 × 109, and k'45 ～ 6 × 106 M-1 s-1. The first and the second types of exchange dominate at low bromide to thallium ratios, (Brtot/Tltot) = R ≤ 2, whereas the third one becomes dominant at higher R values. The activation parameters for the reaction represented by k01 are ΔH* = 38 kj mol-1 and ΔS* = -32 J mol-1 K-1. A mechanism for this reaction is suggested to be a dissociatively activated interchange process. The present results are discussed and compared to the corresponding data for the thallium(III) chloride system. One important result of the present study is the estimation of the rate of water exchange for the hydrated thallium(III) ion, k ～ 3 × 108 s-1, which has not been possible to obtain by any other experimental method. Specific interaction theory calculation has been performed for the TlBrn3-n complexes in order to check the validity of the used equilibrium constants; values of the appropriate specific interaction coefficients are given.
MONO AND BIS(η5-ARYL)THALLIUM(III) COMPLEXES WITH MONOFUNCTIONAL BIDENTATE DITHIOCARBAZATE LIGAND
Sharma, A. K.,Bhushan, B.,Kaushik, N. K.
, p. 29 - 34 (2007/10/02)
Some organometallic compounds of thallium(III) of the type RTl(S2CNHNHC6H5)Br, RTl(S2CNHNHC6H5)2 and R2Tl(S2CNHNHC6H5), where R= cyclopentadienyl, methylcyclopentadienyl, indenyl and fluorenyl groups have been synthesized.These compounds have been characterized on the basis of elemental analyses, IR and PMR spectral studies.Molecular weight determinations and conductance measurements show that these compounds are monomeric nonelectrolytes.Ir spectral studies demonstrate that the dithiocarbazate group behaves as a S-S bonding bidentate ligand.Therefore a coordination number of 4 may be assigned to thallium (III) atom in RTl(S2CNHNHC6H5)Br and R2Tl(S2CNHNHC6H5) and 5 in RTl(S2CHNHC6H5)2.
