Materials Data on NaLaSe2 by Materials Project

Abstract

NaLaSe2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with six equivalent NaSe6 octahedra, edges with four equivalent NaSe6 octahedra, and edges with eight equivalent LaSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.96 Å) and four longer (3.09 Å) Na–Se bond lengths. La3+ is bonded to six Se2- atoms to form LaSe6 octahedra that share corners with six equivalent LaSe6 octahedra, edges with four equivalent LaSe6 octahedra, and edges with eight equivalent NaSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.96 Å) and four longer (3.09 Å) La–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Na1+ and four equivalent La3+ atoms to form a mixture of edge and corner-sharing SeNa2La4 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second Se2- site, Se2- is bonded to four equivalent Na1+ and two equivalent La3+ atoms to form SeNa4La2 octahedra that share corners with six equivalent SeNa4La2 octahedra and edges with twelve SeNa2La4 octahedra. The corner-sharing octahedral tilt angles are 0°.