Materials Data on Sr(LaSe2)2 by Materials Project
Sr(LaSe2)2 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Sr2+ is bonded to eight equivalent Se2- atoms to form distorted SrSe8 hexagonal bipyramids that share corners with eight equivalent LaSe8 hexagonal bipyramids, edges with four equivalent SrSe8 hexagonal bipyramids, and faces with eight equivalent LaSe8 hexagonal bipyramids. There are four shorter (3.12 Å) and four longer (3.30 Å) Sr–Se bond lengths. La3+ is bonded to eight equivalent Se2- atoms to form distorted LaSe8 hexagonal bipyramids that share corners with four equivalent SrSe8 hexagonal bipyramids, corners with four equivalent LaSe8 hexagonal bipyramids, edges with four equivalent LaSe8 hexagonal bipyramids, faces with four equivalent SrSe8 hexagonal bipyramids, and faces with four equivalent LaSe8 hexagonal bipyramids. There are a spread of La–Se bond distances ranging from 3.04–3.28 Å. Se2- is bonded to two equivalent Sr2+ and four equivalent La3+ atoms to form a mixture of distorted corner, edge, and face-sharing SeSr2La4 octahedra. The corner-sharing octahedra tilt angles range from 16–50°.