Na2GeSe3 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 Se(2), one Se(3), and three equivalent Se(1) atoms to form distorted NaSe5 trigonal bipyramids that share corners with two equivalent Ge(1)Se4 tetrahedra, corners with two equivalent Na(1)Se5 trigonal bipyramids, edges with two equivalent Ge(1)Se4 tetrahedra, and edges with two equivalent Na(1)Se5 trigonal bipyramids. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one Se(2), two equivalent Se(1), and three equivalent Se(3) atoms. Ge(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form GeSe4 tetrahedra that share corners with two equivalent Ge(1)Se4 tetrahedra, corners with two equivalent Na(1)Se5 trigonal bipyramids, and edges with two equivalent Na(1)Se5 trigonal bipyramids. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Na(2), three equivalent Na(1), and one Ge(1) atom to form distorted SeNa5Ge pentagonal pyramids that share corners with two equivalent Se(1)Na5Ge pentagonal pyramids, corners with four equivalent Se(3)Na4Ge trigonal bipyramids, edges with three equivalent Se(1)Na5Ge pentagonal pyramids, and edges with three equivalent Se(3)Na4Ge trigonal bipyramids. In the second Se site, Se(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), and two equivalent Ge(1) atoms. In the third Se site, Se(3) is bonded to one Na(1), three equivalent Na(2), and one Ge(1) atom to form SeNa4Ge trigonal bipyramids that share corners with four equivalent Se(1)Na5Ge pentagonal pyramids, corners with two equivalent Se(3)Na4Ge trigonal bipyramids, edges with three equivalent Se(1)Na5Ge pentagonal pyramids, and edges with two equivalent Se(3)Na4Ge trigonal bipyramids.
Na2GeSe3 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 Se(2), one Se(3), and three equivalent Se(1) atoms to form distorted NaSe5 trigonal bipyramids that share corners with two equivalent Ge(1)Se4 tetrahedra, corners with two equivalent Na(1)Se5 trigonal bipyramids, edges with two equivalent Ge(1)Se4 tetrahedra, and edges with two equivalent Na(1)Se5 trigonal bipyramids. The Na(1)-Se(2) bond length is 3.21 Å. The Na(1)-Se(3) bond length is 2.97 Å. There is one shorter (3.01 Å) and two longer (3.08 Å) Na(1)-Se(1) bond lengths. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one Se(2), two equivalent Se(1), and three equivalent Se(3) atoms. The Na(2)-Se(2) bond length is 2.93 Å. There is one shorter (2.96 Å) and one longer (3.30 Å) Na(2)-Se(1) bond length. There are a spread of Na(2)-Se(3) bond distances ranging from 3.01-3.19 Å. Ge(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form GeSe4 tetrahedra that share corners with two equivalent Ge(1)Se4 tetrahedra, corners with two equivalent Na(1)Se5 trigonal bipyramids, and edges with two equivalent Na(1)Se5 trigonal bipyramids. The Ge(1)-Se(1) bond length is 2.32 Å. The Ge(1)-Se(3) bond length is 2.32 Å. There is one shorter (2.40 Å) and one longer (2.41 Å) Ge(1)-Se(2) bond length. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Na(2), three equivalent Na(1), and one Ge(1) atom to form distorted SeNa5Ge pentagonal pyramids that share corners with two equivalent Se(1)Na5Ge pentagonal pyramids, corners with four equivalent Se(3)Na4Ge trigonal bipyramids, edges with three equivalent Se(1)Na5Ge pentagonal pyramids, and edges with three equivalent Se(3)Na4Ge trigonal bipyramids. In the second Se site, Se(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), and two equivalent Ge(1) atoms. In the third Se site, Se(3) is bonded to one Na(1), three equivalent Na(2), and one Ge(1) atom to form SeNa4Ge trigonal bipyramids that share corners with four equivalent Se(1)Na5Ge pentagonal pyramids, corners with two equivalent Se(3)Na4Ge trigonal bipyramids, edges with three equivalent Se(1)Na5Ge pentagonal pyramids, and edges with two equivalent Se(3)Na4Ge trigonal bipyramids.