Design of High-Temperature Syntheses on the Example of the Heavy-Atom Cluster Compound Sn[PtBi6I12]

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Investigations into potential topological materials yielded the new subiodide Sn[PtBi6I12]. The combination of thermal analyses with phase analyses of the products of isothermal ex situ syntheses allowed the establishment of a complex high-temperature synthesis protocol for the crystal growth of the target phase despite the lack of knowledge of the quaternary phase diagram. A special challenge was to prevent the formation of competing compounds of the solid solution series (Bi2xSn1–3x)[PtBi6I12] with x≠0. Sn[PtBi6I12] crystallizes, isostructural to Pb[PtBi6I12], in the rhombohedral space group R (Formula presented.) with lattice parameters a=1583.2(2) pm and c=1089.70(10) pm. The compound consists of cuboctahedral [PtBi6I12]2− clusters and Sn2+ cations in an octahedral coordination between the trigonal faces of two cluster units, thereby concatenating them into infinite linear chains. The chains are connected via Bi...I inter-cluster bridges, creating a high-entropy variant of the NaCl structure type. Sn[PtBi6I12] is a semiconductor with an experimental bandgap of 0.8(1) eV. Fully relativistic density functional theory calculations including an implementation of the bifunctional formalism for the exchange energy indicate a topologically trivial bandgap of 0.81 eV between bands that are dominated by contributions of bismuth and iodine.


Original languageEnglish
Article numbere202200080
JournalZeitschrift fur Anorganische und Allgemeine Chemie
Issue number17
Publication statusPublished - 13 Sept 2022

External IDs

Scopus 85128086041
Mendeley 8a43f0cf-caf1-39b6-b1bf-94f7af90a232
ORCID /0000-0002-2391-6025/work/142250224


DFG Classification of Subject Areas according to Review Boards

Subject groups, research areas, subject areas according to Destatis

ASJC Scopus subject areas


  • bifunctional formalism, bismuth, cluster compounds, crystal growth, spin-orbit coupling