Materials Data on EuYSi4N7 by Materials Project
EuYSi4N7 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Eu2+ is bonded to twelve N3- atoms to form distorted EuN12 cuboctahedra that share corners with twelve equivalent EuN12 cuboctahedra, edges with twelve SiN4 tetrahedra, and faces with four equivalent YN6 octahedra. There are a spread of Eu–N bond distances ranging from 2.90–3.17 Å. Y3+ is bonded to six N3- atoms to form YN6 octahedra that share corners with twelve SiN4 tetrahedra and faces with four equivalent EuN12 cuboctahedra. All Y–N bond lengths are 2.32 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four N3- atoms to form SiN4 tetrahedra that share corners with three equivalent YN6 octahedra, corners with six SiN4 tetrahedra, and edges with three equivalent EuN12 cuboctahedra. The corner-sharing octahedra tilt angles range from 57–62°. There are a spread of Si–N bond distances ranging from 1.72–1.97 Å. In the second Si4+ site, Si4+ is bonded to four N3- atoms to form SiN4 tetrahedra that share corners with three equivalent YN6 octahedra, corners with six equivalent SiN4 tetrahedra, and edges with three equivalent EuN12 cuboctahedra. The corner-sharing octahedral tilt angles are 56°. There is three shorter (1.71 Å) and one longer (1.88 Å) Si–N bond length. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a tetrahedral geometry to four Si4+ atoms. In the second N3- site, N3- is bonded in a distorted trigonal planar geometry to two equivalent Eu2+, one Y3+, and two Si4+ atoms. In the third N3- site, N3- is bonded in a 3-coordinate geometry to two equivalent Eu2+, one Y3+, and two equivalent Si4+ atoms.