Materials Data on Ho2MgS4 by Materials Project
MgHo2S4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to four S2- atoms to form MgS4 trigonal pyramids that share corners with three equivalent HoS6 pentagonal pyramids and a faceface with one HoS6 pentagonal pyramid. There are a spread of Mg–S bond distances ranging from 2.34–2.47 Å. There are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Ho–S bond distances ranging from 2.67–3.23 Å. In the second Ho3+ site, Ho3+ is bonded to six S2- atoms to form distorted HoS6 pentagonal pyramids that share corners with three equivalent MgS4 trigonal pyramids, edges with two equivalent HoS6 pentagonal pyramids, and a faceface with one MgS4 trigonal pyramid. There are a spread of Ho–S bond distances ranging from 2.57–2.86 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to one Mg2+ and four Ho3+ atoms. In the second S2- site, S2- is bonded in a T-shaped geometry to one Mg2+ and two Ho3+ atoms. In the third S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ho3+ atoms.