CaYSiO5 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a distorted pentagonal planar geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. Y(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form YO6 octahedra that share corners with two equivalent Y(1)O6 octahedra and corners with four equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. Si(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with four equivalent Y(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-54°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ca(1) and two equivalent Y(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Y(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Ca(1), one Y(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Y(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ca(1), one Y(1), and one Si(1) atom.
CaYSiO5 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a distorted pentagonal planar geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The Ca(1)-O(1) bond length is 2.24 Å. The Ca(1)-O(2) bond length is 2.39 Å. The Ca(1)-O(3) bond length is 2.41 Å. The Ca(1)-O(4) bond length is 2.41 Å. The Ca(1)-O(5) bond length is 2.42 Å. Y(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form YO6 octahedra that share corners with two equivalent Y(1)O6 octahedra and corners with four equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. The Y(1)-O(2) bond length is 2.33 Å. The Y(1)-O(3) bond length is 2.25 Å. The Y(1)-O(4) bond length is 2.32 Å. The Y(1)-O(5) bond length is 2.25 Å. There is one shorter (2.23 Å) and one longer (2.26 Å) Y(1)-O(1) bond length. Si(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with four equivalent Y(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-54°. The Si(1)-O(2) bond length is 1.66 Å. The Si(1)-O(3) bond length is 1.67 Å. The Si(1)-O(4) bond length is 1.65 Å. The Si(1)-O(5) bond length is 1.65 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ca(1) and two equivalent Y(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Y(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Ca(1), one Y(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Y(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ca(1), one Y(1), and one Si(1) atom.