DOE OSTI2020
Mg(ScS2)2 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one Mg(ScS2)2 sheet oriented in the (0, 0, 1) direction. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four S2- atoms to form MgS4 tetrahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent ScS6 octahedra, and corners with six ScS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are one shorter (2.43 Å) and three longer (2.46 Å) Mg–S bond lengths. In the second Mg2+ site, Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share a cornercorner with one MgS4 tetrahedra, corners with five ScS4 tetrahedra, edges with two equivalent MgS6 octahedra, and edges with four equivalent ScS6 octahedra. There are a spread of Mg–S bond distances ranging from 2.64–2.70 Å. There are four inequivalent Sc3+ sites. In the first Sc3+ site, Sc3+ is bonded to four S2- atoms to form ScS4 tetrahedra that share a cornercorner with one ScS6 octahedra, corners with two equivalent MgS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four ScS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are a spread of Sc–S bond distances ranging from 2.42–2.47 Å. In the second Sc3+ site, Sc3+ is bonded to six S2- atoms to form ScS6 octahedra that share corners with two equivalent MgS4 tetrahedra, corners with four ScS4 tetrahedra, edges with two equivalent ScS6 octahedra, and edges with four equivalent MgS6 octahedra. There are a spread of Sc–S bond distances ranging from 2.58–2.68 Å. In the third Sc3+ site, Sc3+ is bonded to four S2- atoms to form ScS4 tetrahedra that share a cornercorner with one ScS6 octahedra, corners with two equivalent MgS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four ScS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are a spread of Sc–S bond distances ranging from 2.42–2.48 Å. In the fourth Sc3+ site, Sc3+ is bonded to four S2- atoms to form ScS4 tetrahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent ScS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four ScS4 tetrahedra. The corner-sharing octahedral tilt angles are 60°. There are a spread of Sc–S bond distances ranging from 2.43–2.47 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Mg2+ and two Sc3+ atoms to form distorted SMg2Sc2 trigonal pyramids that share corners with five SMg2Sc2 tetrahedra, corners with four equivalent SMgSc3 trigonal pyramids, edges with two SMg2Sc2 tetrahedra, and an edgeedge with one SMg2Sc2 trigonal pyramid. In the second S2- site, S2- is bonded to two Mg2+ and two equivalent Sc3+ atoms to form distorted SMg2Sc2 tetrahedra that share corners with four equivalent SMg2Sc2 tetrahedra, corners with five SMg2Sc2 trigonal pyramids, an edgeedge with one SMg2Sc2 tetrahedra, and edges with two SMgSc3 trigonal pyramids. In the third S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two Sc3+ atoms. In the fourth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Sc3+ atoms. In the fifth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two Sc3+ atoms. In the sixth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two Sc3+ atoms. In the seventh S2- site, S2- is bonded to one Mg2+ and three Sc3+ atoms to form distorted SMgSc3 trigonal pyramids that share corners with five SMg2Sc2 tetrahedra, corners with four equivalent SMg2Sc2 trigonal pyramids, edges with two SMg2Sc2 tetrahedra, and an edgeedge with one SMgSc3 trigonal pyramid. In the eighth S2- site, S2- is bonded to two equivalent Mg2+ and two Sc3+ atoms to form distorted SMg2Sc2 tetrahedra that share corners with four equivalent SMg2Sc2 tetrahedra, corners with five SMg2Sc2 trigonal pyramids, an edgeedge with one SMg2Sc2 tetrahedra, and edges with two SMgSc3 trigonal pyramids.