Na2CoGeO4 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 Ge(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 Ge(1)O4 tetrahedra and corners with eight equivalent Na(1)O4 tetrahedra. Ge(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form GeO4 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 to two equivalent Na(1), one Co(1), and one Ge(1) atom to form corner-sharing ONa2CoGe tetrahedra. In the second O site, O(2) is bonded to two equivalent Na(1), one Co(1), and one Ge(1) atom to form distorted corner-sharing ONa2CoGe tetrahedra. In the third O site, O(3) is bonded to two equivalent Na(1), one Co(1), and one Ge(1) atom to form corner-sharing ONa2CoGe tetrahedra.
Na2CoGeO4 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 Ge(1)O4 tetrahedra. The Na(1)-O(1) bond length is 2.27 Å. The Na(1)-O(2) bond length is 2.28 Å. There is one shorter (2.32 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 Ge(1)O4 tetrahedra and corners with eight equivalent Na(1)O4 tetrahedra. The Co(1)-O(1) bond length is 1.96 Å. The Co(1)-O(2) bond length is 2.00 Å. Both Co(1)-O(3) bond lengths are 2.05 Å. Ge(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form GeO4 tetrahedra that share corners with four equivalent Co(1)O4 tetrahedra and corners with eight equivalent Na(1)O4 tetrahedra. The Ge(1)-O(1) bond length is 1.78 Å. The Ge(1)-O(2) bond length is 1.78 Å. Both Ge(1)-O(3) bond lengths are 1.80 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), one Co(1), and one Ge(1) atom to form corner-sharing ONa2CoGe tetrahedra. In the second O site, O(2) is bonded to two equivalent Na(1), one Co(1), and one Ge(1) atom to form distorted corner-sharing ONa2CoGe tetrahedra. In the third O site, O(3) is bonded to two equivalent Na(1), one Co(1), and one Ge(1) atom to form corner-sharing ONa2CoGe tetrahedra.