DOI: 10.17188/1190707
title: Materials Data on Hf6Cr5Si7 by Materials Project

description: Hf6Cr5Si7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are six inequivalent Hf sites. In the first Hf site, Hf is bonded in a 7-coordinate geometry to two equivalent Cr and seven Si atoms. Both Hf–Cr bond lengths are 2.98 Å. There are a spread of Hf–Si bond distances ranging from 2.69–2.83 Å. In the second Hf site, Hf is bonded in a 7-coordinate geometry to two equivalent Cr and seven Si atoms. Both Hf–Cr bond lengths are 2.98 Å. There are a spread of Hf–Si bond distances ranging from 2.78–2.85 Å. In the third Hf site, Hf is bonded in a 6-coordinate geometry to three Cr and six Si atoms. There are two shorter (2.85 Å) and one longer (2.96 Å) Hf–Cr bond lengths. There are a spread of Hf–Si bond distances ranging from 2.66–2.84 Å. In the fourth Hf site, Hf is bonded in a 6-coordinate geometry to two equivalent Cr and six Si atoms. Both Hf–Cr bond lengths are 2.83 Å. There are a spread of Hf–Si bond distances ranging from 2.66–2.83 Å. In the fifth Hf site, Hf is bonded in a 10-coordinate geometry to five Cr and five Si atoms. There are a spread of Hf–Cr bond distances ranging from 2.94–3.07 Å. There are a spread of Hf–Si bond distances ranging from 2.79–2.95 Å. In the sixth Hf site, Hf is bonded to seven Si atoms to form distorted HfSi7 pentagonal bipyramids that share corners with four equivalent CrHf5Cr3Si4 cuboctahedra, corners with two equivalent HfSi7 pentagonal bipyramids, and edges with two equivalent HfSi7 pentagonal bipyramids. There are a spread of Hf–Si bond distances ranging from 2.67–2.89 Å. There are three inequivalent Cr sites. In the first Cr site, Cr is bonded in a 7-coordinate geometry to one Cr and six Si atoms. The Cr–Cr bond length is 2.42 Å. There are a spread of Cr–Si bond distances ranging from 2.44–2.66 Å. In the second Cr site, Cr is bonded in a 12-coordinate geometry to four Hf, two equivalent Cr, and three Si atoms. Both Cr–Cr bond lengths are 2.38 Å. There are one shorter (2.36 Å) and two longer (2.42 Å) Cr–Si bond lengths. In the third Cr site, Cr is bonded to five Hf, three Cr, and four Si atoms to form distorted CrHf5Cr3Si4 cuboctahedra that share corners with two equivalent CrHf5Cr3Si4 cuboctahedra, corners with two equivalent HfSi7 pentagonal bipyramids, and faces with two equivalent CrHf5Cr3Si4 cuboctahedra. There are one shorter (2.53 Å) and one longer (2.56 Å) Cr–Cr bond lengths. There are a spread of Cr–Si bond distances ranging from 2.44–2.50 Å. There are six inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to five Hf and four Cr atoms. In the second Si site, Si is bonded in a 9-coordinate geometry to five Hf and four equivalent Cr atoms. In the third Si site, Si is bonded in a 10-coordinate geometry to seven Hf, one Cr, and two equivalent Si atoms. There are one shorter (2.50 Å) and one longer (2.59 Å) Si–Si bond lengths. In the fourth Si site, Si is bonded in a 9-coordinate geometry to four Hf and five Cr atoms. In the fifth Si site, Si is bonded in a 9-coordinate geometry to five Hf and four Cr atoms. In the sixth Si site, Si is bonded in a 9-coordinate geometry to five Hf and four Cr atoms.