Na2CoSiO4 is beta beryllia-derived structured and crystallizes in the orthorhombic Pmn2_1 space group. Na(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra, corners with four equivalent Co(1)O4 tetrahedra, and corners with four equivalent Si(1)O4 tetrahedra. Co(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CoO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra and corners with eight equivalent Na(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with four equivalent Co(1)O4 tetrahedra and corners with eight equivalent Na(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one Co(1), and one Si(1) atom. In the second O site, O(2) is bonded to two equivalent Na(1), one Co(1), and one Si(1) atom to form distorted corner-sharing ONa2CoSi tetrahedra. In the third O site, O(3) is bonded to two equivalent Na(1), one Co(1), and one Si(1) atom to form distorted corner-sharing ONa2CoSi tetrahedra.
Na2CoSiO4 is beta beryllia-derived structured and crystallizes in the orthorhombic Pmn2_1 space group. Na(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra, corners with four equivalent Co(1)O4 tetrahedra, and corners with four equivalent Si(1)O4 tetrahedra. The Na(1)-O(1) bond length is 2.29 Å. The Na(1)-O(2) bond length is 2.26 Å. There is one shorter (2.31 Å) and one longer (2.35 Å) Na(1)-O(3) bond length. Co(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CoO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra and corners with eight equivalent Na(1)O4 tetrahedra. The Co(1)-O(1) bond length is 1.99 Å. The Co(1)-O(2) bond length is 1.96 Å. Both Co(1)-O(3) bond lengths are 2.05 Å. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with four equivalent Co(1)O4 tetrahedra and corners with eight equivalent Na(1)O4 tetrahedra. The Si(1)-O(1) bond length is 1.65 Å. The Si(1)-O(2) bond length is 1.65 Å. Both Si(1)-O(3) bond lengths are 1.67 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one Co(1), and one Si(1) atom. In the second O site, O(2) is bonded to two equivalent Na(1), one Co(1), and one Si(1) atom to form distorted corner-sharing ONa2CoSi tetrahedra. In the third O site, O(3) is bonded to two equivalent Na(1), one Co(1), and one Si(1) atom to form distorted corner-sharing ONa2CoSi tetrahedra.