Premium
Lithium Argyrodites with Phosphorus and Arsenic: Order and Disorder of Lithium Atoms, Crystal Chemistry, and Phase Transitions
Author(s) -
Kong ShiaoTong,
Deiseroth HansJörg,
Reiner Christof,
Gün Özgül,
Neumann Elmar,
Ritter Clemens,
Zahn Dirk
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200902470
Subject(s) - lithium (medication) , crystallography , chemistry , crystal structure , neutron diffraction , crystal (programming language) , single crystal , phase transition , phase (matter) , crystal chemistry , physics , thermodynamics , medicine , organic chemistry , computer science , programming language , endocrinology
Crystal chemical data of high‐ (HT) and low‐temperature (LT) modifications of lithium argyrodites with the compositions Li 7 PCh 6 (Ch=S, Se), Li 6 PCh 5 X (X=Cl, Br, I), Li 6 AsS 5 Br, and Li 6 AsCh 5 I (Ch=S, Se) based on single‐crystal, powder X‐ray (113 K< T <503 K) and neutron measurements (5 K< T <293 K) are presented. In the HT modifications, the Li atoms are strongly disordered over a fraction of the available tetrahedral holes, whereas in the LT modifications they occupy ordered crystallographic positions with a pronounced site preference that is analysed on a crystal chemical basis. The Ch/X partial structures remain nearly unchanged upon the reversible phase transitions. Crystal chemical and crystallographic relations between HT and LT modifications based on the Frank–Kasper model of tetrahedral close packing are discussed. X‐ray single‐crystal data for HT‐Li 6 PS 5 I show the electron density of the disordered Li to be smeared out over an extended region preferably inside face‐sharing double tetrahedra. A series of temperature‐dependent powder neutron data for Li 6 PS 5 I gives clear evidence for an HT/LT phase transition at ≈175 K with an ordering of the Li atoms in different polyhedra with coordination numbers between three and four.