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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ta4SiTe4 by Materials Project

Ta4SiTe4 crystallizes in the orthorhombic Pbam space group. The structure is one-dimensional and consists of two Ta4SiTe4 ribbons oriented in the (1, 0, 0) direction. there are two inequivalent Ta3+ sites. In the first Ta3+ site, Ta3+ is bonded to two equivalent Si4- and four Te2- atoms to form a mixture of distorted edge, face, and corner-sharing TaSi2Te4 octahedra. The corner-sharing octahedra tilt angles range from 40–69°. Both Ta–Si bond lengths are 2.60 Å. There are two shorter (2.86 Å) and two longer (2.94 Å) Ta–Te bond lengths. In the second Ta3+ site, Ta3+ is bonded to two equivalent Si4- and four Te2- atoms to form a mixture of distorted edge, face, and corner-sharing TaSi2Te4 octahedra. The corner-sharing octahedra tilt angles range from 40–70°. Both Ta–Si bond lengths are 2.61 Å. There are two shorter (2.86 Å) and two longer (2.94 Å) Ta–Te bond lengths. Si4- is bonded in a 10-coordinate geometry to eight Ta3+ and two equivalent Si4- atoms. Both Si–Si bond lengths are 2.42 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 4-coordinate geometry to four Ta3+ atoms. In the second Te2- site, Te2- is bonded in a 4-coordinate geometry to four Ta3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta3SiTe6 by Materials Project

Ta3SiTe6 crystallizes in the orthorhombic Pnma space group. The structure is two-dimensional and consists of two Ta3SiTe6 sheets oriented in the (0, 0, 1) direction. there are three inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to one Si4- and six Te+1.83- atoms to form distorted TaSiTe6 pentagonal bipyramids that share an edgeedge with one SiTa4Te4 hexagonal bipyramid, edges with four TaSiTe6 pentagonal bipyramids, and a faceface with one TaSiTe6 pentagonal bipyramid. The Ta–Si bond length is 2.84 Å. There are a spread of Ta–Te bond distances ranging from 2.80–2.88 Å. In the second Ta5+ site, Ta5+ is bonded in a 8-coordinate geometry to two equivalent Si4- and six Te+1.83- atoms. There are one shorter (2.83 Å) and one longer (2.84 Å) Ta–Si bond lengths. There are a spread of Ta–Te bond distances ranging from 2.83–2.95 Å. In the third Ta5+ site, Ta5+ is bonded to one Si4- and six Te+1.83- atoms to form distorted TaSiTe6 pentagonal bipyramids that share edges with two equivalent SiTa4Te4 hexagonal bipyramids, edges with two equivalent TaSiTe6 pentagonal bipyramids, and a faceface with one TaSiTe6 pentagonal bipyramid. The Ta–Si bond length is 2.73 Å. There are a spread of Ta–Te bond distances ranging from 2.76–2.96 Å. Si4- is bonded to four Ta5+ and four Te+1.83- atoms to form distorted SiTa4Te4 hexagonal bipyramids that share corners with two equivalent SiTa4Te4 hexagonal bipyramids and edges with three TaSiTe6 pentagonal bipyramids. There are two shorter (2.71 Å) and two longer (2.76 Å) Si–Te bond lengths. There are three inequivalent Te+1.83- sites. In the first Te+1.83- site, Te+1.83- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the second Te+1.83- site, Te+1.83- is bonded in a 4-coordinate geometry to three Ta5+ and one Si4- atom. In the third Te+1.83- site, Te+1.83- is bonded in a 4-coordinate geometry to three Ta5+ and one Si4- atom.

36 MATERIALS SCIENCE↗