Materials Data on Si9Ni25 by Materials Project
Ni25Si9 crystallizes in the trigonal P-3 space group. The structure is three-dimensional and consists of one nickel molecule and one Ni8Si3 framework. In the Ni8Si3 framework, there are six inequivalent Ni+1.44+ sites. In the first Ni+1.44+ site, Ni+1.44+ is bonded to four Si4- atoms to form a mixture of distorted edge and corner-sharing NiSi4 tetrahedra. There are a spread of Ni–Si bond distances ranging from 2.25–2.59 Å. In the second Ni+1.44+ site, Ni+1.44+ is bonded in a trigonal non-coplanar geometry to three equivalent Si4- atoms. All Ni–Si bond lengths are 2.28 Å. In the third Ni+1.44+ site, Ni+1.44+ is bonded to four Si4- atoms to form a mixture of edge and corner-sharing NiSi4 tetrahedra. All Ni–Si bond lengths are 2.35 Å. In the fourth Ni+1.44+ site, Ni+1.44+ is bonded to four Si4- atoms to form a mixture of edge and corner-sharing NiSi4 tetrahedra. There are three shorter (2.42 Å) and one longer (2.51 Å) Ni–Si bond lengths. In the fifth Ni+1.44+ site, Ni+1.44+ is bonded in a trigonal non-coplanar geometry to three Si4- atoms. There are two shorter (2.35 Å) and one longer (2.42 Å) Ni–Si bond lengths. In the sixth Ni+1.44+ site, Ni+1.44+ is bonded in a 3-coordinate geometry to four equivalent Si4- atoms. There are a spread of Ni–Si bond distances ranging from 2.27–2.76 Å. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to ten Ni+1.44+ atoms. In the second Si4- site, Si4- is bonded in a 10-coordinate geometry to ten Ni+1.44+ atoms. In the third Si4- site, Si4- is bonded in a body-centered cubic geometry to eight Ni+1.44+ atoms.