Materials Data on Si7(Ni2Au)2 by Materials Project
Si7(Ni2Au)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Ni+1.50+ sites. In the first Ni+1.50+ site, Ni+1.50+ is bonded in a body-centered cubic geometry to one Au1- and seven Si+0.57- atoms. The Ni–Au bond length is 2.63 Å. There are a spread of Ni–Si bond distances ranging from 2.27–2.35 Å. In the second Ni+1.50+ site, Ni+1.50+ is bonded in a body-centered cubic geometry to two equivalent Au1- and six Si+0.57- atoms. There are one shorter (2.68 Å) and one longer (2.70 Å) Ni–Au bond lengths. There are a spread of Ni–Si bond distances ranging from 2.31–2.35 Å. Au1- is bonded in a 9-coordinate geometry to three Ni+1.50+ and six Si+0.57- atoms. There are a spread of Au–Si bond distances ranging from 2.55–3.01 Å. There are four inequivalent Si+0.57- sites. In the first Si+0.57- site, Si+0.57- is bonded in a 10-coordinate geometry to four Ni+1.50+, one Au1-, and two equivalent Si+0.57- atoms. Both Si–Si bond lengths are 2.71 Å. In the second Si+0.57- site, Si+0.57- is bonded to four Ni+1.50+ and six Si+0.57- atoms to form a mixture of distorted edge, face, and corner-sharing SiSi6Ni4 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.66–2.70 Å. In the third Si+0.57- site, Si+0.57- is bonded in a 6-coordinate geometry to three Ni+1.50+, three equivalent Au1-, and two equivalent Si+0.57- atoms. In the fourth Si+0.57- site, Si+0.57- is bonded in a 10-coordinate geometry to four equivalent Ni+1.50+, four equivalent Au1-, and two equivalent Si+0.57- atoms.