[Tl7]7- Clusters in Mixed Alkali Metal Thallides Cs7.29K5.71Tl13 and Cs3.45K3.55Tl7

Vanessa F Schwinghammer; Stefanie Gärtner

doi:10.1021/acs.inorgchem.3c04034

[Tl₇]^7- Clusters in Mixed Alkali Metal Thallides Cs_7.29K_5.71Tl₁₃ and Cs_3.45K_3.55Tl₇

Inorg Chem. 2024 Feb 28. doi: 10.1021/acs.inorgchem.3c04034. Online ahead of print.

Authors

Vanessa F Schwinghammer¹, Stefanie Gärtner^{1

2}

Affiliations

¹ Institute of Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
² Central Analytics, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.

PMID: 38416695
DOI: 10.1021/acs.inorgchem.3c04034

Abstract

Investigations in the ternary system Cs-K-Tl resulted in the unexpected formation of new ternary thallides Cs_7.29K_5.71Tl₁₃ and Cs_3.45K_3.55Tl₇. Single crystal X-ray structure analyses of both compounds reveal the presence of isolated Tl cluster units. Cs_7.29K_5.71Tl₁₃ crystallizes in the monoclinic space group C2/c (a = 30.7792(9) Å, b = 11.000(2) Å, c = 14.0291(4) Å, β = 112.676(4)°, Z = 4) and contains [Tl₆]^6- and [Tl₇]^7- clusters as thallium subunits. Cs_3.45K_3.55Tl₇ crystallizes in the tetragonal space group I4₁/a (a = 13.6177(2) Å, c = 25.5573(8) Å, Z = 8) and contains [Tl₇]^7- clusters exclusively. The formation of Cs_7.29K_5.71Tl₁₃ is obtained after slow cooling in addition to that of Cs_3.45K_3.55Tl₇ and can be suppressed by quenching the stoichiometric mixture. First dissolution experiments in liquid ammonia suggest thallium and amide as final oxidation products. Full relativistic band structure calculations of Cs₄K₃Tl₇ and Cs₈K₅Tl₁₃ showed a (pseudo) band gap around E_F for both compounds.