CaH2 is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded in a 9-coordinate geometry to four equivalent H(2) and five equivalent H(1) atoms. There are two inequivalent H sites. In the first H site, H(2) is bonded to four equivalent Ca(1) atoms to form HCa4 tetrahedra that share corners with eight equivalent H(1)Ca5 square pyramids, corners with eight equivalent H(2)Ca4 tetrahedra, edges with six equivalent H(1)Ca5 square pyramids, and edges with two equivalent H(2)Ca4 tetrahedra. In the second H site, H(1) is bonded to five equivalent Ca(1) atoms to form distorted HCa5 square pyramids that share corners with eight equivalent H(1)Ca5 square pyramids, corners with eight equivalent H(2)Ca4 tetrahedra, edges with six equivalent H(1)Ca5 square pyramids, and edges with six equivalent H(2)Ca4 tetrahedra.
CaH2 is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded in a 9-coordinate geometry to four equivalent H(2) and five equivalent H(1) atoms. There are a spread of Ca(1)-H(2) bond distances ranging from 2.24-2.28 Å. There are a spread of Ca(1)-H(1) bond distances ranging from 2.39-2.61 Å. There are two inequivalent H sites. In the first H site, H(2) is bonded to four equivalent Ca(1) atoms to form HCa4 tetrahedra that share corners with eight equivalent H(1)Ca5 square pyramids, corners with eight equivalent H(2)Ca4 tetrahedra, edges with six equivalent H(1)Ca5 square pyramids, and edges with two equivalent H(2)Ca4 tetrahedra. In the second H site, H(1) is bonded to five equivalent Ca(1) atoms to form distorted HCa5 square pyramids that share corners with eight equivalent H(1)Ca5 square pyramids, corners with eight equivalent H(2)Ca4 tetrahedra, edges with six equivalent H(1)Ca5 square pyramids, and edges with six equivalent H(2)Ca4 tetrahedra.