Solubility, complex formation, and redox reactions in the Tl2O3-HCN/CN--H2O system. Crystal structures of the cyano compounds Tl(CN)(3)center dot H2O, Na Tl(CN)(4) center dot 3H(2)O, K Tl(CN)41, and Tl-I Tl-III(CN)41 and of (Tl2C2O4)-C-I
2005 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 44, no 7, 2347-2357 p.Article in journal (Refereed) Published
Thallium(III) oxide can be dissolved in water in the presence of strongly complexing cyanide ions. TI111 is leached from its oxide both by aqueous solutions of hydrogen cyanide and by alkali-metal cyanides. The dominating cyano complex of thallium(III) obtained by dissolution of TI2O3 in HCN is [TI(CN)(3)(aq)] as shown by (TI)-T-205 NMR. The TI(CN)(3) species has been selectively extracted into diethyl ether from aqueous solution with the ratio CN-/TI111 = 3. When aqueous solutions of the MCN (M = Na+, K+) salts are used to dissolve thallium(III) oxide, the equilibrium in liquid phase is fully shifted to the [TI(CN)(4)](-) complex. The TI(CN)(3) and TI(CN)(4)(-) species have for the first time been synthesized in the solid state as TI(CN)(3)(H2O)-H-. (1), M[TI(CN)(4)] (M = TI (2) and K (3)), and Na[TI(CN)(4)](.)3H(2)O (4) salts, and their structures have been determined by single-crystal X-ray diffraction. In the crystal structure of 1, the thallium(III) ion has a trigonal bipyramidal coordination with three cyanide ions in the equatorial plane, while an oxygen atom of the water molecule and a nitrogen atom from a cyanide ligand, attached to a neighboring thallium complex, form a linear O-TI-N fragment. In the three compounds of the tetracyano-thallium(III) complex, 2-4, the [TI(CN)(4)](-) unit has a distorted tetrahedral geometry. Along with the acidic leaching (enhanced by TI111-CN- complex formation), an effective reductive dissolution of the thallium(III) oxide can also take place in the TI2O3-HCN-H2O system yielding thallium(l), while hydrogen cyanide is oxidized to cyanogen. The latter is hydrolyzed in aqueous solution giving rise to a number of products including (CONH2)(2), NCO-, and NH4+ detected by N-14 NMR. The crystalline compounds, TI1[TI111(CN)(4)], (TI2C2O4)-C-1, and (CONH2)(2), have been obtained as products of the redox reactions in the system.
Place, publisher, year, edition, pages
2005. Vol. 44, no 7, 2347-2357 p.
potassium tetroxalate, molecular-structure, aqueous-solution, nmr, thallium(iii), perchlorate, diffraction, chloride, bromide, c-13
IdentifiersURN: urn:nbn:se:kth:diva-14648DOI: 10.1021/ic0485918ISI: 000228054200030ScopusID: 2-s2.0-16344384019OAI: oai:DiVA.org:kth-14648DiVA: diva2:332689
QC 201005252010-08-052010-08-05Bibliographically approved