DOE OSTI2020
Sm2Sc3Si4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sm is bonded in a 7-coordinate geometry to seven Si atoms. There are a spread of Sm–Si bond distances ranging from 2.98–3.37 Å. There are two inequivalent Sc sites. In the first Sc site, Sc is bonded to six Si atoms to form distorted corner-sharing ScSi6 octahedra. The corner-sharing octahedra tilt angles range from 53–54°. There are a spread of Sc–Si bond distances ranging from 2.82–2.99 Å. In the second Sc site, Sc is bonded in a 6-coordinate geometry to six Si atoms. There are a spread of Sc–Si bond distances ranging from 2.74–2.85 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to two equivalent Sm, six Sc, and one Si atom. The Si–Si bond length is 2.57 Å. In the second Si site, Si is bonded in a 9-coordinate geometry to four equivalent Sm, four Sc, and one Si atom. In the third Si site, Si is bonded in a 9-coordinate geometry to four equivalent Sm, four Sc, and one Si atom. The Si–Si bond length is 2.53 Å.