Materials Data on NaCaH3 by Materials Project

Abstract

NaCaH3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Na1+ is bonded to five H1- atoms to form distorted NaH5 square pyramids that share corners with five equivalent CaH7 pentagonal bipyramids, corners with two equivalent NaH5 square pyramids, edges with three equivalent CaH7 pentagonal bipyramids, and an edgeedge with one NaH5 square pyramid. There are a spread of Na–H bond distances ranging from 2.26–2.36 Å. Ca2+ is bonded to seven H1- atoms to form distorted CaH7 pentagonal bipyramids that share corners with five equivalent NaH5 square pyramids, edges with five equivalent CaH7 pentagonal bipyramids, and edges with three equivalent NaH5 square pyramids. There are a spread of Ca–H bond distances ranging from 2.27–2.40 Å. There are three inequivalent H1- sites. In the first H1- site, H1- is bonded to two equivalent Na1+ and two equivalent Ca2+ atoms to form HNa2Ca2 tetrahedra that share corners with six HNa2Ca2 tetrahedra, corners with eight equivalent HNaCa3 trigonal pyramids, and edges with three HNa2Ca2 tetrahedra. In the second H1- site, H1- is bonded to one Na1+ and three equivalent Ca2+ atoms to form HNaCa3 trigonal pyramids that share corners with twelve HNa2Ca2 tetrahedra, corners with two equivalent HNaCa3 trigonal pyramids, edges with two equivalent HNa2Ca2 tetrahedra, and edges with two equivalent HNaCa3 trigonal pyramids. In the third H1- site, H1- is bonded to two equivalent Na1+ and two equivalent Ca2+ atoms to form HNa2Ca2 tetrahedra that share corners with six HNa2Ca2 tetrahedra, corners with four equivalent HNaCa3 trigonal pyramids, edges with three HNa2Ca2 tetrahedra, and edges with two equivalent HNaCa3 trigonal pyramids.