Ca(BH4)2 crystallizes in the orthorhombic Fddd space group. Ca(1) is bonded to four equivalent H(2) and eight equivalent H(1) atoms to form CaH12 cuboctahedra that share edges with four equivalent Ca(1)H12 cuboctahedra and edges with six equivalent B(1)H4 tetrahedra. B(1) is bonded to two equivalent H(1) and two equivalent H(2) atoms to form BH4 tetrahedra that share edges with three equivalent Ca(1)H12 cuboctahedra. There are two inequivalent H sites. In the first H site, H(2) is bonded in a distorted water-like geometry to one Ca(1) and one B(1) atom. In the second H site, H(1) is bonded in a distorted single-bond geometry to two equivalent Ca(1) and one B(1) atom.
Ca(BH4)2 crystallizes in the orthorhombic Fddd space group. Ca(1) is bonded to four equivalent H(2) and eight equivalent H(1) atoms to form CaH12 cuboctahedra that share edges with four equivalent Ca(1)H12 cuboctahedra and edges with six equivalent B(1)H4 tetrahedra. All Ca(1)-H(2) bond lengths are 2.32 Å. There are four shorter (2.43 Å) and four longer (2.60 Å) Ca(1)-H(1) bond lengths. B(1) is bonded to two equivalent H(1) and two equivalent H(2) atoms to form BH4 tetrahedra that share edges with three equivalent Ca(1)H12 cuboctahedra. Both B(1)-H(1) bond lengths are 1.23 Å. Both B(1)-H(2) bond lengths are 1.22 Å. There are two inequivalent H sites. In the first H site, H(2) is bonded in a distorted water-like geometry to one Ca(1) and one B(1) atom. In the second H site, H(1) is bonded in a distorted single-bond geometry to two equivalent Ca(1) and one B(1) atom.