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Synthesis, structure and spin‐crossover transition of The Cluster Compound Nb 6 I 11−x Br x (0 ⩽ x ⩽ 2.7)
Author(s) -
Yoshiasa Akira,
Borrmann Horst,
Simon Arndt
Publication year - 1994
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.19946200730
Subject(s) - crystallography , spin crossover , phase transition , homogeneous , crystal structure , lattice constant , cluster (spacecraft) , lattice (music) , chemistry , materials science , condensed matter physics , thermodynamics , physics , programming language , computer science , diffraction , optics , acoustics
The homogeneous phase Nb 6 I 11−x Br x (0 ⩽ x ⩽ 2.7) is synthesized from Nb 3 Br 8 , Nb 3 I 8 and Nb in sealed Nb capsules at 1 130 K. A second‐order phase transition is found as for the composition Nb 6 I 11 itself, changing the space group from P2 1 cn (low temperatures) to Pccn, accompanied by a spin‐crossover from a doublet to a quartet state. With increasing Br content the lattice constants decrease and the transition temperature shifts from 274 to 170 K while the transition interval is broadened simultaneously. Single crystal investigations for x = 0.5 and 2.3, each at 110 and 298 K, indicate a preferred substitution of one of the bridging I positions (I6) by Br atoms.