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The Bismuth Subiodides Bi 8 Pt 5 I 3 and Bi 16 Pt 11 I 6 – Layered Metals with Covalent Platinum Networks
Author(s) -
Rasche Bertold,
Schnelle Walter,
Ruck Michael
Publication year - 2015
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201500120
Subject(s) - bismuth , intermetallic , crystallography , platinum , iodide , tetragonal crystal system , chemistry , trigonal pyramidal molecular geometry , materials science , inorganic chemistry , crystal structure , alloy , metallurgy , biochemistry , catalysis
Black shiny platelets of Bi 8 Pt 5 I 3 and Bi 16 Pt 11 I 6 were crystallized from melts of the metals and BiI 3 . Despite very similar compositions and close peritectics, a protocol for targeted synthesis could be developed based on differences of the decomposition pressures. Bi 8 Pt 5 I 3 has a monoclinic crystal structure [space group C 2/ m ; a = 1850.7(2) pm, b = 391.46(3) pm, c = 1340.5(1) pm, β = 113.28(1)°], in which corrugated intermetallic layers alternate with monolayers of non‐coordinating iodide ions. The platinum atoms are in square, trigonal‐prismatic, or capped trigonal‐prismatic coordination by bismuth atoms. Additional covalent bonding between platinum atoms defines flat stripes of five atoms width inside the intermetallic layer. Bi 16 Pt 11 I 6 crystallizes in the acentric tetragonal space group P 42 1 2 with a = 1386.6(1) pm and c = 924.5(1) pm. Corresponding to the higher transition‐metal content, the covalent network of platinum atoms is two‐dimensional. The node connectivity in the network is three or four; the total coordination number of all platinum atoms is ten. Single layers of iodide ions separate the intermetallic layers. Two‐thirds of the iodide ions are coordinating bismuth atoms that protrude from the intermetallic layer, forming [BiI 4 ] squares. Temperature‐dependent electrical resistivity and magnetic susceptibility measurements on polycrystalline powders indicate that Bi 8 Pt 5 I 3 and Bi 16 Pt 11 I 6 are diamagnetic metals. The calculated electronic band structures confirm pseudo two‐dimensional metallic character only for Bi 8 Pt 5 I 3 .