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Perovskite Distortion Inverted: Crystal Structures of ( A 3 N)As ( A = Mg, Ca, Sr, Ba)
Author(s) -
Stoiber Dominik,
Niewa Rainer
Publication year - 2019
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.201800295
Subject(s) - orthorhombic crystal system , alkaline earth metal , barium , crystallography , crystal structure , strontium , perovskite (structure) , metal , chemistry , distortion (music) , materials science , inorganic chemistry , metallurgy , organic chemistry , amplifier , optoelectronics , cmos
Powder samples of the compounds ( A 3 N)As ( A = Mg, Ca, Sr, Ba) were prepared by reacting the respective alkaline earth metal nitrides and arsenic in nickel ampoules. (Mg 3 N)As crystallizes in a cubic unit cell (space group Pm 3 m , no. 221) with inverse perovskite structure. The analogous compounds of calcium, strontium, and barium crystallize in an orthorhombic unit cell (space group Pnma , no. 62) as distorted inverse perovskites in the GdFeO 3 structure type. The degree of distortion was quantified based on a newly developed vectorial comparison of the atomic sites of coordination polyhedra with the ideal positions (PolyDis). Based on this analysis, the distortion increases with the size of the alkaline earth metal cation.