DOE OSTI2020
Tm3Pt23Si11 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Tm3+ is bonded to eight equivalent Pt+1.26- atoms to form distorted corner-sharing TmPt8 cuboctahedra. All Tm–Pt bond lengths are 3.16 Å. There are four inequivalent Pt+1.26- sites. In the first Pt+1.26- site, Pt+1.26- is bonded in a distorted square co-planar geometry to four equivalent Si+1.82+ atoms. All Pt–Si bond lengths are 2.58 Å. In the second Pt+1.26- site, Pt+1.26- is bonded in a 3-coordinate geometry to two equivalent Tm3+ and three Si+1.82+ atoms. There are a spread of Pt–Si bond distances ranging from 2.43–2.46 Å. In the third Pt+1.26- site, Pt+1.26- is bonded to four Si+1.82+ atoms to form a mixture of edge and corner-sharing PtSi4 tetrahedra. There are one shorter (2.43 Å) and three longer (2.50 Å) Pt–Si bond lengths. In the fourth Pt+1.26- site, Pt+1.26- is bonded to four Si+1.82+ atoms to form a mixture of distorted edge and corner-sharing PtSi4 tetrahedra. All Pt–Si bond lengths are 2.51 Å. There are three inequivalent Si+1.82+ sites. In the first Si+1.82+ site, Si+1.82+ is bonded in a 7-coordinate geometry to seven Pt+1.26- atoms. In the second Si+1.82+ site, Si+1.82+ is bonded in a body-centered cubic geometry to eight Pt+1.26- atoms. In the third Si+1.82+ site, Si+1.82+ is bonded in a 7-coordinate geometry to seven Pt+1.26- atoms.