Materials Data on Hf2Cr4Si5 by Materials Project
Hf2Cr4Si5 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. Hf4+ is bonded to seven Si4- atoms to form a mixture of corner, edge, and face-sharing HfSi7 pentagonal bipyramids. There are a spread of Hf–Si bond distances ranging from 2.62–2.79 Å. There are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded in a 8-coordinate geometry to two equivalent Cr3+ and six Si4- atoms. Both Cr–Cr bond lengths are 2.46 Å. There are a spread of Cr–Si bond distances ranging from 2.45–2.55 Å. In the second Cr3+ site, Cr3+ is bonded in a 7-coordinate geometry to seven Si4- atoms. There are a spread of Cr–Si bond distances ranging from 2.41–2.80 Å. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to four equivalent Hf4+ and five Cr3+ atoms. In the second Si4- site, Si4- is bonded in a 10-coordinate geometry to four equivalent Hf4+, four equivalent Cr3+, and two equivalent Si4- atoms. Both Si–Si bond lengths are 2.46 Å. In the third Si4- site, Si4- is bonded in a 10-coordinate geometry to one Hf4+, six Cr3+, and three equivalent Si4- atoms. There are one shorter (2.34 Å) and two longer (2.71 Å) Si–Si bond lengths.