Ca2Fe(PO6)2 crystallizes in the triclinic P-1 space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. Fe(1) is bonded to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one Ca(1) and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Ca(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Ca(1) and one Fe(1) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Ca(1) and one Fe(1) atom.
Ca2Fe(PO6)2 crystallizes in the triclinic P-1 space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. The Ca(1)-O(1) bond length is 2.44 Å. The Ca(1)-O(2) bond length is 2.32 Å. The Ca(1)-O(3) bond length is 2.61 Å. The Ca(1)-O(5) bond length is 2.45 Å. The Ca(1)-O(6) bond length is 2.46 Å. There is one shorter (2.43 Å) and one longer (2.44 Å) Ca(1)-O(4) bond length. Fe(1) is bonded to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra. Both Fe(1)-O(3) bond lengths are 1.94 Å. Both Fe(1)-O(5) bond lengths are 1.80 Å. Both Fe(1)-O(6) bond lengths are 1.82 Å. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. The P(1)-O(1) bond length is 1.54 Å. The P(1)-O(2) bond length is 1.53 Å. The P(1)-O(3) bond length is 1.61 Å. The P(1)-O(4) bond length is 1.54 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one Ca(1) and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Ca(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Ca(1) and one Fe(1) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Ca(1) and one Fe(1) atom.