Synthesis, structure, and electronic and physical properties of the two SrZrS3 modifications

We uncovered a new modification of SrZrS3 at low temperature, which forms the NH4CdCl3 type. The earlier reported type (GdFeO3) is the high temperature modification. The structures of both SrZrS3 modifications were determined by single crystal X-ray diffraction. Both crystallize in the orthorhombic crystal system, space group Pnma. The cell dimensions for alpha-SrZrS3 (NH4CdCl3 type) are: a = 8.5254(7) angstrom, b = 3.8255(3) angstrom, c = 13.9246(12) angstrom V = 454.14(6) angstrom(3) (Z = 4), and for beta-SrZrS3 (GdFeO3 type): a = 7.1080(5) angstrom, b = 9.7715(7) angstrom, c = 6.7406(5) angstrom, V 468.17(6) angstrom(3) (Z = 4). The alpha form consists of building blocks of one-dimensional chains with edge-sharing ZrS6 octahedra and intervening alkaline earth cations (Sr). The beta-form is comprised of a three-dimensional network of corner-sharing ZrS6 octahedra, and the structure can be viewed as a distorted perovskite. (c) 2005 Elsevier SAS. All rights reserved.