Na2CrSiCO7 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. Cr(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-50°. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one Cr(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to two equivalent Na(1), one Cr(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Cr(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Cr(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Na(1), one Cr(1), and one Si(1) atom.
Na2CrSiCO7 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Na(1)-O(1) bond length is 2.27 Å. The Na(1)-O(2) bond length is 2.44 Å. The Na(1)-O(3) bond length is 2.33 Å. The Na(1)-O(4) bond length is 2.41 Å. The Na(1)-O(5) bond length is 2.71 Å. The Na(1)-O(6) bond length is 2.56 Å. Cr(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra. The Cr(1)-O(2) bond length is 2.04 Å. The Cr(1)-O(3) bond length is 2.06 Å. The Cr(1)-O(4) bond length is 1.88 Å. The Cr(1)-O(5) bond length is 1.98 Å. Both Cr(1)-O(6) bond lengths are 1.90 Å. Si(1) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-50°. The Si(1)-O(4) bond length is 1.65 Å. The Si(1)-O(5) bond length is 1.64 Å. Both Si(1)-O(6) bond lengths are 1.65 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.25 Å. The C(1)-O(2) bond length is 1.32 Å. The C(1)-O(3) bond length is 1.33 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one Cr(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to two equivalent Na(1), one Cr(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Cr(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Cr(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Na(1), one Cr(1), and one Si(1) atom.