DOI: 10.17188/1720471
title: Materials Data on HfTaSi by Materials Project

description: HfTaSi crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are seven inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five Ta, and seven Si atoms. There are a spread of Hf–Hf bond distances ranging from 3.17–3.28 Å. There are one shorter (3.14 Å) and four longer (3.15 Å) Hf–Ta bond lengths. There are a spread of Hf–Si bond distances ranging from 3.09–3.16 Å. In the second Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven Ta, and five Si atoms. There are two shorter (3.28 Å) and one longer (3.42 Å) Hf–Hf bond lengths. There are a spread of Hf–Ta bond distances ranging from 3.05–3.21 Å. There are a spread of Hf–Si bond distances ranging from 3.02–3.17 Å. In the third Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven Ta, and five Si atoms. There are one shorter (3.23 Å) and two longer (3.28 Å) Hf–Hf bond lengths. There are a spread of Hf–Ta bond distances ranging from 3.05–3.21 Å. There are a spread of Hf–Si bond distances ranging from 3.02–3.17 Å. In the fourth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five Ta, and seven Si atoms. There are one shorter (3.17 Å) and one longer (3.23 Å) Hf–Hf bond lengths. There are one shorter (3.14 Å) and four longer (3.15 Å) Hf–Ta bond lengths. There are a spread of Hf–Si bond distances ranging from 3.09–3.16 Å. In the fifth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven Ta, and five Si atoms. The Hf–Hf bond length is 3.42 Å. There are a spread of Hf–Ta bond distances ranging from 3.05–3.21 Å. There are a spread of Hf–Si bond distances ranging from 3.02–3.17 Å. In the sixth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven Ta, and five Si atoms. There are one shorter (3.23 Å) and two longer (3.28 Å) Hf–Hf bond lengths. There are a spread of Hf–Ta bond distances ranging from 3.05–3.21 Å. There are a spread of Hf–Si bond distances ranging from 3.02–3.17 Å. In the seventh Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five Ta, and seven Si atoms. There are one shorter (3.14 Å) and four longer (3.15 Å) Hf–Ta bond lengths. There are a spread of Hf–Si bond distances ranging from 3.09–3.16 Å. There are three inequivalent Ta sites. In the first Ta site, Ta is bonded to six Hf and six Si atoms to form distorted TaHf6Si6 cuboctahedra that share corners with four equivalent SiHf6Ta4Si2 cuboctahedra, corners with fourteen TaHf6Si6 cuboctahedra, edges with six TaHf6Si6 cuboctahedra, faces with four equivalent TaHf6Ta4Si2 cuboctahedra, and faces with six equivalent SiHf6Ta4Si2 cuboctahedra. There are a spread of Ta–Si bond distances ranging from 2.60–2.70 Å. In the second Ta site, Ta is bonded to six Hf, four Ta, and two equivalent Si atoms to form distorted TaHf6Ta4Si2 cuboctahedra that share corners with four equivalent SiHf6Ta4Si2 cuboctahedra, corners with eight TaHf6Si6 cuboctahedra, edges with two equivalent TaHf6Ta4Si2 cuboctahedra, faces with six equivalent SiHf6Ta4Si2 cuboctahedra, and faces with ten TaHf6Si6 cuboctahedra. There are a spread of Ta–Ta bond distances ranging from 2.60–2.79 Å. Both Ta–Si bond lengths are 2.69 Å. In the third Ta site, Ta is bonded to six Hf, four equivalent Ta, and two equivalent Si atoms to form distorted TaHf6Ta4Si2 cuboctahedra that share corners with four equivalent SiHf6Ta4Si2 cuboctahedra, corners with six TaHf6Si6 cuboctahedra, edges with six TaHf6Si6 cuboctahedra, faces with six equivalent SiHf6Ta4Si2 cuboctahedra, and faces with eight equivalent TaHf6Ta4Si2 cuboctahedra. Both Ta–Si bond lengths are 2.68 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded to six Hf, four Ta, and two equivalent Si atoms to form distorted SiHf6Ta4Si2 cuboctahedra that share corners with eight TaHf6Si6 cuboctahedra, edges with six equivalent SiHf6Ta4Si2 cuboctahedra, faces with two equivalent SiHf6Ta4Si2 cuboctahedra, and faces with twelve TaHf6Si6 cuboctahedra. Both Si–Si bond lengths are 2.73 Å. In the second Si site, Si is bonded in a 12-coordinate geometry to six Hf, two equivalent Ta, and four Si atoms. There are one shorter (2.57 Å) and one longer (2.87 Å) Si–Si bond lengths.