Materials Data on HfFeSi2 by Materials Project

Abstract

HfFeSi2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to four Fe and eight Si atoms. There are two shorter (2.92 Å) and two longer (3.05 Å) Hf–Fe bond lengths. There are a spread of Hf–Si bond distances ranging from 2.71–2.87 Å. In the second Hf site, Hf is bonded in a 7-coordinate geometry to four equivalent Fe and seven Si atoms. All Hf–Fe bond lengths are 2.96 Å. There are a spread of Hf–Si bond distances ranging from 2.65–2.85 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a 12-coordinate geometry to four equivalent Hf and six Si atoms. There are a spread of Fe–Si bond distances ranging from 2.31–2.47 Å. In the second Fe site, Fe is bonded to four Hf, two equivalent Fe, and six Si atoms to form a mixture of distorted face, edge, and corner-sharing FeHf4Fe2Si6 cuboctahedra. Both Fe–Fe bond lengths are 2.57 Å. There are a spread of Fe–Si bond distances ranging from 2.39–2.45 Å. There are five inequivalent Si sites. In the first Si site, Si is bonded in a 10-coordinate geometry to six Hf, two equivalent Fe, and two equivalent Si atoms. There are one shorter (2.53 Å) and one longer (2.62 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 12-coordinate geometry to four Hf and four equivalent Fe atoms. In the third Si site, Si is bonded in a 7-coordinate geometry to three Hf, three Fe, and one Si atom. The Si–Si bond length is 2.33 Å. In the fourth Si site, Si is bonded in a 7-coordinate geometry to three Hf and four equivalent Fe atoms. In the fifth Si site, Si is bonded in a 12-coordinate geometry to four equivalent Hf, two equivalent Fe, and one Si atom. The Si–Si bond length is 2.48 Å.