Materials Data on Ta4Co4Si7 by Materials Project

Abstract

Ta4Co4Si7 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Ta3+ sites. In the first Ta3+ site, Ta3+ is bonded to seven Si+2.86- atoms to form a mixture of edge, corner, and face-sharing TaSi7 pentagonal bipyramids. There are a spread of Ta–Si bond distances ranging from 2.64–2.82 Å. In the second Ta3+ site, Ta3+ is bonded to seven Si+2.86- atoms to form a mixture of edge, corner, and face-sharing TaSi7 pentagonal bipyramids. There are a spread of Ta–Si bond distances ranging from 2.63–2.83 Å. Co2+ is bonded in a 6-coordinate geometry to six Si+2.86- atoms. There are a spread of Co–Si bond distances ranging from 2.31–2.35 Å. There are four inequivalent Si+2.86- sites. In the first Si+2.86- site, Si+2.86- is bonded in a 6-coordinate geometry to one Ta3+, four equivalent Co2+, and one Si+2.86- atom. The Si–Si bond length is 2.37 Å. In the second Si+2.86- site, Si+2.86- is bonded in a 10-coordinate geometry to eight Ta3+ and two equivalent Si+2.86- atoms. There are one shorter (2.48 Å) and one longer (2.50 Å) Si–Si bond lengths. In the third Si+2.86- site, Si+2.86- is bonded in a 9-coordinate geometry to five Ta3+ and four equivalent Co2+ atoms. In the fourth Si+2.86- site, Si+2.86- is bonded in a 12-coordinate geometry to four Ta3+ and four equivalent Co2+ atoms.