Materials Data on SrPr12Al12Si18(N2O)18 by Materials Project

Abstract

SrPr12Al12Si18(N2O)18 crystallizes in the cubic I-43m space group. The structure is three-dimensional. Sr is bonded in a 12-coordinate geometry to twelve equivalent N atoms. All Sr–N bond lengths are 2.90 Å. Pr is bonded in a 5-coordinate geometry to four N and three O atoms. There are a spread of Pr–N bond distances ranging from 2.45–2.93 Å. There are two shorter (2.48 Å) and one longer (2.58 Å) Pr–O bond lengths. Al is bonded in a rectangular see-saw-like geometry to three N and one O atom. There is one shorter (1.91 Å) and two longer (1.92 Å) Al–N bond length. The Al–O bond length is 2.19 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded to three N and one O atom to form corner-sharing SiN3O tetrahedra. There is two shorter (1.75 Å) and one longer (1.85 Å) Si–N bond length. The Si–O bond length is 1.69 Å. In the second Si site, Si is bonded in a rectangular see-saw-like geometry to four N atoms. There is two shorter (1.75 Å) and two longer (1.78 Å) Si–N bond length. There are three inequivalent N sites. In the first N site, N is bonded to one Pr, one Al, and two equivalent Si atoms to form distorted NPrAlSi2 tetrahedra that share corners with two equivalent NPrAlSi2 tetrahedra and corners with two equivalent OPr4 tetrahedra. In the second N site, N is bonded in a 3-coordinate geometry to one Sr, two equivalent Al, and one Si atom. In the third N site, N is bonded in a 5-coordinate geometry to three equivalent Pr and two Si atoms. There are two inequivalent O sites. In the first O site, O is bonded to four equivalent Pr atoms to form OPr4 tetrahedra that share corners with four equivalent NPrAlSi2 tetrahedra and corners with four equivalent OPr4 tetrahedra. In the second O site, O is bonded in a 1-coordinate geometry to one Pr, one Al, and one Si atom.