Materials Data on CeSe2 by Materials Project

Abstract

CeSe2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Ce4+ sites. In the first Ce4+ site, Ce4+ is bonded to six Se2- atoms to form distorted CeSe6 pentagonal pyramids that share corners with three CeSe7 pentagonal bipyramids, corners with two equivalent CeSe6 pentagonal pyramids, and edges with five CeSe7 pentagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 2.79–3.00 Å. In the second Ce4+ site, Ce4+ is bonded to seven Se2- atoms to form distorted CeSe7 pentagonal bipyramids that share corners with two equivalent CeSe7 pentagonal bipyramids, corners with two equivalent CeSe6 pentagonal pyramids, edges with four equivalent CeSe7 pentagonal bipyramids, and edges with two equivalent CeSe6 pentagonal pyramids. There are a spread of Ce–Se bond distances ranging from 2.89–3.00 Å. In the third Ce4+ site, Ce4+ is bonded to seven Se2- atoms to form distorted CeSe7 pentagonal bipyramids that share corners with two equivalent CeSe7 pentagonal bipyramids, a cornercorner with one CeSe6 pentagonal pyramid, edges with four equivalent CeSe7 pentagonal bipyramids, and edges with three equivalent CeSe6 pentagonal pyramids. There are a spread of Ce–Se bond distances ranging from 2.87–2.95 Å. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three Ce4+ atoms. In the second Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to three Ce4+ atoms. In the third Se2- site, Se2- is bonded to four Ce4+ atoms to form a mixture of distorted edge and corner-sharing SeCe4 tetrahedra. In the fourth Se2- site, Se2- is bonded to four Ce4+ atoms to form a mixture of distorted edge and corner-sharing SeCe4 trigonal pyramids. In the fifth Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to three Ce4+ atoms. In the sixth Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to three Ce4+ atoms.