Na2Ge2O5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(3), and three equivalent O(2) atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Na(2)O5 trigonal bipyramids,  an edgeedge with one Ge(1)O4 tetrahedra, edges with two equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Na(2)O5 trigonal bipyramids. In the second Na site, Na(2) is bonded to one O(2), one O(4), and three equivalent O(3) atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Na(2)O5 trigonal bipyramids,  an edgeedge with one Ge(2)O4 tetrahedra, edges with two equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Na(2)O5 trigonal bipyramids. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form GeO4 tetrahedra that share corners with three equivalent Ge(2)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Na(2)O5 trigonal bipyramids, and  an edgeedge with one Na(1)O5 trigonal bipyramid. In the second Ge site, Ge(2) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form GeO4 tetrahedra that share corners with three equivalent Ge(1)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Na(2)O5 trigonal bipyramids, and  an edgeedge with one Na(2)O5 trigonal bipyramid. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Na(1), one Ge(1), and one Ge(2) atom. In the second O site, O(2) is bonded to one Na(2), three equivalent Na(1), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing ONa4Ge trigonal bipyramids. In the third O site, O(3) is bonded to one Na(1), three equivalent Na(2), and one Ge(2) atom to form a mixture of distorted corner and edge-sharing ONa4Ge trigonal bipyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(2), one Ge(1), and one Ge(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Ge(1) and one Ge(2) atom.
Na2Ge2O5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(3), and three equivalent O(2) atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Na(2)O5 trigonal bipyramids,  an edgeedge with one Ge(1)O4 tetrahedra, edges with two equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Na(2)O5 trigonal bipyramids. The Na(1)-O(1) bond length is 2.40 Å. The Na(1)-O(3) bond length is 2.39 Å. There are a spread of Na(1)-O(2) bond distances ranging from 2.40-2.70 Å. In the second Na site, Na(2) is bonded to one O(2), one O(4), and three equivalent O(3) atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Na(2)O5 trigonal bipyramids,  an edgeedge with one Ge(2)O4 tetrahedra, edges with two equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Na(2)O5 trigonal bipyramids. The Na(2)-O(2) bond length is 2.40 Å. The Na(2)-O(4) bond length is 2.45 Å. There are a spread of Na(2)-O(3) bond distances ranging from 2.39-2.71 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form GeO4 tetrahedra that share corners with three equivalent Ge(2)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Na(2)O5 trigonal bipyramids, and  an edgeedge with one Na(1)O5 trigonal bipyramid. The Ge(1)-O(1) bond length is 1.80 Å. The Ge(1)-O(2) bond length is 1.73 Å. The Ge(1)-O(4) bond length is 1.79 Å. The Ge(1)-O(5) bond length is 1.78 Å. In the second Ge site, Ge(2) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form GeO4 tetrahedra that share corners with three equivalent Ge(1)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Na(2)O5 trigonal bipyramids, and  an edgeedge with one Na(2)O5 trigonal bipyramid. The Ge(2)-O(1) bond length is 1.79 Å. The Ge(2)-O(3) bond length is 1.72 Å. The Ge(2)-O(4) bond length is 1.81 Å. The Ge(2)-O(5) bond length is 1.78 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Na(1), one Ge(1), and one Ge(2) atom. In the second O site, O(2) is bonded to one Na(2), three equivalent Na(1), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing ONa4Ge trigonal bipyramids. In the third O site, O(3) is bonded to one Na(1), three equivalent Na(2), and one Ge(2) atom to form a mixture of distorted corner and edge-sharing ONa4Ge trigonal bipyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(2), one Ge(1), and one Ge(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Ge(1) and one Ge(2) atom.