Ca3(PO4)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to two equivalent O(2) and four equivalent O(4) atoms. In the second Ca site, Ca(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CaO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Ca(2)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. In the second P site, P(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-57°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Ca(2) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ca(2) and one P(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one P(2) atom.
Ca3(PO4)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to two equivalent O(2) and four equivalent O(4) atoms. Both Ca(1)-O(2) bond lengths are 2.37 Å. There are two shorter (2.43 Å) and two longer (2.84 Å) Ca(1)-O(4) bond lengths. In the second Ca site, Ca(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CaO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Ca(2)O6 octahedra. The Ca(2)-O(2) bond length is 2.35 Å. The Ca(2)-O(3) bond length is 2.28 Å. There is one shorter (2.28 Å) and one longer (2.29 Å) Ca(2)-O(1) bond length. There is one shorter (2.51 Å) and one longer (2.59 Å) Ca(2)-O(4) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. Both P(1)-O(1) bond lengths are 1.55 Å. Both P(1)-O(2) bond lengths are 1.56 Å. In the second P site, P(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-57°. Both P(2)-O(3) bond lengths are 1.52 Å. Both P(2)-O(4) bond lengths are 1.59 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Ca(2) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ca(2) and one P(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one P(2) atom.