Ca2Fe3Si3O14 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one O(2), one O(4), two equivalent O(5), and two equivalent O(8) atoms. In the second Ca site, Ca(2) is bonded to one O(3), one O(6), one O(7), two equivalent O(10), and two equivalent O(5) atoms to form distorted CaO7 pentagonal bipyramids that share corners with two equivalent Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and  an edgeedge with one Si(3)O4 tetrahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(11), one O(7), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and  an edgeedge with one Ca(2)O7 pentagonal bipyramid. In the second Fe site, Fe(2) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Ca(2)O7 pentagonal bipyramids. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(4), and two equivalent O(5) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with three equivalent Ca(2)O7 pentagonal bipyramids, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. In the second Si site, Si(2) is bonded to one O(11), one O(2), and two equivalent O(10) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, and corners with two equivalent Ca(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-61°. In the third Si site, Si(3) is bonded to one O(3), one O(7), and two equivalent O(8) atoms to form SiO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  an edgeedge with one Ca(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 50-56°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), two equivalent Fe(2), and one Si(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(2), one Si(1), and one Si(3) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Ca(1) and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), one Ca(2), one Fe(2), and one Si(1) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Ca(2) and two equivalent Fe(2) atoms. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Ca(2), two equivalent Fe(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ca(1), one Fe(1), and one Si(3) atom. In the ninth O site, O(9) is bonded in a water-like geometry to two equivalent Fe(1) atoms. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ca(2), one Fe(1), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one Si(2) atom.
Ca2Fe3Si3O14 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one O(2), one O(4), two equivalent O(5), and two equivalent O(8) atoms. The Ca(1)-O(2) bond length is 2.63 Å. The Ca(1)-O(4) bond length is 2.24 Å. Both Ca(1)-O(5) bond lengths are 2.53 Å. Both Ca(1)-O(8) bond lengths are 2.32 Å. In the second Ca site, Ca(2) is bonded to one O(3), one O(6), one O(7), two equivalent O(10), and two equivalent O(5) atoms to form distorted CaO7 pentagonal bipyramids that share corners with two equivalent Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and  an edgeedge with one Si(3)O4 tetrahedra. The Ca(2)-O(3) bond length is 2.58 Å. The Ca(2)-O(6) bond length is 2.32 Å. The Ca(2)-O(7) bond length is 2.44 Å. Both Ca(2)-O(10) bond lengths are 2.37 Å. Both Ca(2)-O(5) bond lengths are 2.49 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(11), one O(7), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and  an edgeedge with one Ca(2)O7 pentagonal bipyramid. The Fe(1)-O(1) bond length is 1.91 Å. The Fe(1)-O(10) bond length is 1.97 Å. The Fe(1)-O(11) bond length is 2.05 Å. The Fe(1)-O(7) bond length is 2.13 Å. The Fe(1)-O(8) bond length is 1.97 Å. The Fe(1)-O(9) bond length is 1.86 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Ca(2)O7 pentagonal bipyramids. Both Fe(2)-O(2) bond lengths are 2.14 Å. Both Fe(2)-O(5) bond lengths are 2.05 Å. Both Fe(2)-O(6) bond lengths are 1.88 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(4), and two equivalent O(5) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with three equivalent Ca(2)O7 pentagonal bipyramids, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. The Si(1)-O(3) bond length is 1.70 Å. The Si(1)-O(4) bond length is 1.59 Å. Both Si(1)-O(5) bond lengths are 1.67 Å. In the second Si site, Si(2) is bonded to one O(11), one O(2), and two equivalent O(10) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, and corners with two equivalent Ca(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-61°. The Si(2)-O(11) bond length is 1.65 Å. The Si(2)-O(2) bond length is 1.67 Å. Both Si(2)-O(10) bond lengths are 1.64 Å. In the third Si site, Si(3) is bonded to one O(3), one O(7), and two equivalent O(8) atoms to form SiO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  an edgeedge with one Ca(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 50-56°. The Si(3)-O(3) bond length is 1.66 Å. The Si(3)-O(7) bond length is 1.65 Å. Both Si(3)-O(8) bond lengths are 1.62 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), two equivalent Fe(2), and one Si(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(2), one Si(1), and one Si(3) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Ca(1) and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), one Ca(2), one Fe(2), and one Si(1) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Ca(2) and two equivalent Fe(2) atoms. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Ca(2), two equivalent Fe(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ca(1), one Fe(1), and one Si(3) atom. In the ninth O site, O(9) is bonded in a water-like geometry to two equivalent Fe(1) atoms. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ca(2), one Fe(1), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one Si(2) atom.