SrCaSn(PO4)2 crystallizes in the triclinic P-1 space group. Sr(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(8), two equivalent O(1), and two equivalent O(6) atoms. Ca(1) is bonded to one O(1), one O(2), one O(4), one O(7), and two equivalent O(5) atoms to form distorted CaO6 pentagonal pyramids that share  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Ca(1)O6 pentagonal pyramid, and  an edgeedge with one P(1)O4 tetrahedra. Sn(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), one O(5), one O(8), and two equivalent O(7) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Ca(1)O6 pentagonal pyramid and  an edgeedge with one Ca(1)O6 pentagonal pyramid. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Sr(1), one Ca(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Sr(1), one Ca(1), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(1), one Sn(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Ca(1), one Sn(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 1-coordinate geometry to two equivalent Ca(1), one Sn(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 1-coordinate geometry to two equivalent Sr(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a 1-coordinate geometry to one Ca(1), two equivalent Sn(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Sr(1), one Sn(1), and one P(2) atom.
SrCaSn(PO4)2 crystallizes in the triclinic P-1 space group. Sr(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(8), two equivalent O(1), and two equivalent O(6) atoms. The Sr(1)-O(2) bond length is 2.60 Å. The Sr(1)-O(3) bond length is 2.51 Å. The Sr(1)-O(4) bond length is 3.11 Å. The Sr(1)-O(8) bond length is 2.78 Å. There is one shorter (2.61 Å) and one longer (2.72 Å) Sr(1)-O(1) bond length. There is one shorter (2.50 Å) and one longer (2.93 Å) Sr(1)-O(6) bond length. Ca(1) is bonded to one O(1), one O(2), one O(4), one O(7), and two equivalent O(5) atoms to form distorted CaO6 pentagonal pyramids that share  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Ca(1)O6 pentagonal pyramid, and  an edgeedge with one P(1)O4 tetrahedra. The Ca(1)-O(1) bond length is 2.55 Å. The Ca(1)-O(2) bond length is 2.35 Å. The Ca(1)-O(4) bond length is 2.35 Å. The Ca(1)-O(7) bond length is 2.36 Å. There is one shorter (2.47 Å) and one longer (2.69 Å) Ca(1)-O(5) bond length. Sn(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), one O(5), one O(8), and two equivalent O(7) atoms. The Sn(1)-O(3) bond length is 2.24 Å. The Sn(1)-O(4) bond length is 2.36 Å. The Sn(1)-O(5) bond length is 2.73 Å. The Sn(1)-O(8) bond length is 2.30 Å. There is one shorter (2.64 Å) and one longer (2.73 Å) Sn(1)-O(7) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Ca(1)O6 pentagonal pyramid and  an edgeedge with one Ca(1)O6 pentagonal pyramid. The P(1)-O(1) bond length is 1.56 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.56 Å. The P(1)-O(7) bond length is 1.56 Å. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids. The P(2)-O(4) bond length is 1.59 Å. The P(2)-O(5) bond length is 1.59 Å. The P(2)-O(6) bond length is 1.53 Å. The P(2)-O(8) bond length is 1.56 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Sr(1), one Ca(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Sr(1), one Ca(1), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(1), one Sn(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Ca(1), one Sn(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 1-coordinate geometry to two equivalent Ca(1), one Sn(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 1-coordinate geometry to two equivalent Sr(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a 1-coordinate geometry to one Ca(1), two equivalent Sn(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Sr(1), one Sn(1), and one P(2) atom.