Structure, ordering, and bonding of half antiperovskites: PbNi 3/2S and BiPd 3/2S

• Published in: Progress in solid state chemistry Vol. 35; no. 2; pp. 309 - 327
• Main Authors: Weihrich, Richard, Matar, Samir F., Eyert, Volker, Rau, Franz, Zabel, Manfred, Andratschke, Martina, Anusca, Irina, Bernert, Thomas
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2007
• Subjects: ASW; DFT; ECOV; Half antiperovskite; LDA; Ordering; Parkerite; Shandite; DFT; Shandite; Parkerite; ASW; ECOV; Ordering; LDA; Half antiperovskite
• ISSN: 0079-6786; 1873-1643
• DOI: 10.1016/j.progsolidstchem.2007.01.011

In a model study the crystal structures of shandite (Pb 2Ni 3S 2), parkerite (Bi 2Ni 3S 2) and their Pd homologues are investigated in terms of ordered half antiperovskites AM 3/2S (A = Pb, Bi; M = Ni, Pd). This addresses fundamental questions on the structural relations, ordering and chemical bonding. From crystal structure investigations a new cubic parkerite variant is presented for Bi 2Pd 3S 2 that fits in an ordering model equivalently to shandite and parkerite. Type–antitype relations to ordered oxygen deficit perovskites are presented. With the relation to the superconductor Ni 3MgC a model is deduced that provides the complete crystal structure and symmetry in terms of the Ni and Pd ordering in antiperovskite superstructures. Therein a systematic ab initio investigation on the relative stability of shandite and parkerite structures is carried out for the first time. From the DFT modelling results the preferences of the ordering variants and the distinct differences in the atomic coordination spheres are discussed. The bonding in the systems is investigated by site projected density of states and covalent bond energy calculations.