Materials Data on Pr2Sc3Si4 by Materials Project
Pr2Sc3Si4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Pr+3.50+ is bonded to seven Si4- atoms to form distorted PrSi7 pentagonal bipyramids that share corners with four equivalent ScSi6 octahedra, corners with six equivalent PrSi7 pentagonal bipyramids, corners with five equivalent ScSi6 pentagonal pyramids, edges with two equivalent PrSi7 pentagonal bipyramids, edges with three equivalent ScSi6 pentagonal pyramids, faces with two equivalent ScSi6 octahedra, faces with three equivalent PrSi7 pentagonal bipyramids, and faces with three equivalent ScSi6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 45–55°. There are a spread of Pr–Si bond distances ranging from 3.02–3.42 Å. There are two inequivalent Sc3+ sites. In the first Sc3+ site, Sc3+ is bonded to six Si4- atoms to form distorted ScSi6 pentagonal pyramids that share corners with three equivalent ScSi6 octahedra, corners with five equivalent PrSi7 pentagonal bipyramids, corners with four equivalent ScSi6 pentagonal pyramids, edges with three equivalent PrSi7 pentagonal bipyramids, edges with three equivalent ScSi6 pentagonal pyramids, faces with two equivalent ScSi6 octahedra, faces with three equivalent PrSi7 pentagonal bipyramids, and a faceface with one ScSi6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 40°. There are a spread of Sc–Si bond distances ranging from 2.77–2.86 Å. In the second Sc3+ site, Sc3+ is bonded to six Si4- atoms to form ScSi6 octahedra that share corners with four equivalent ScSi6 octahedra, corners with eight equivalent PrSi7 pentagonal bipyramids, corners with six equivalent ScSi6 pentagonal pyramids, faces with four equivalent PrSi7 pentagonal bipyramids, and faces with four equivalent ScSi6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 53–54°. There are a spread of Sc–Si bond distances ranging from 2.86–3.03 Å. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to four equivalent Pr+3.50+, four Sc3+, and one Si4- atom. The Si–Si bond length is 2.59 Å. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to two equivalent Pr+3.50+, six Sc3+, and one Si4- atom. In the third Si4- site, Si4- is bonded in a 9-coordinate geometry to four equivalent Pr+3.50+, four Sc3+, and one Si4- atom. The Si–Si bond length is 2.53 Å.