Na2ZnSe2 crystallizes in the orthorhombic Ibam space group. Na(1) is bonded in a 7-coordinate geometry to two equivalent Zn(1) and five equivalent Se(1) atoms. Zn(1) is bonded to four equivalent Na(1) and four equivalent Se(1) atoms to form distorted ZnNa4Se4 tetrahedra that share corners with twelve equivalent Se(1)Na5Zn2 pentagonal bipyramids, edges with four equivalent Se(1)Na5Zn2 pentagonal bipyramids, and faces with two equivalent Zn(1)Na4Se4 tetrahedra. Se(1) is bonded to five equivalent Na(1) and two equivalent Zn(1) atoms to form distorted SeNa5Zn2 pentagonal bipyramids that share corners with eight equivalent Se(1)Na5Zn2 pentagonal bipyramids, corners with six equivalent Zn(1)Na4Se4 tetrahedra, edges with six equivalent Se(1)Na5Zn2 pentagonal bipyramids, edges with two equivalent Zn(1)Na4Se4 tetrahedra, and faces with two equivalent Se(1)Na5Zn2 pentagonal bipyramids.
Na2ZnSe2 crystallizes in the orthorhombic Ibam space group. Na(1) is bonded in a 7-coordinate geometry to two equivalent Zn(1) and five equivalent Se(1) atoms. Both Na(1)-Zn(1) bond lengths are 3.16 Å. There are a spread of Na(1)-Se(1) bond distances ranging from 2.91-3.17 Å. Zn(1) is bonded to four equivalent Na(1) and four equivalent Se(1) atoms to form distorted ZnNa4Se4 tetrahedra that share corners with twelve equivalent Se(1)Na5Zn2 pentagonal bipyramids, edges with four equivalent Se(1)Na5Zn2 pentagonal bipyramids, and faces with two equivalent Zn(1)Na4Se4 tetrahedra. All Zn(1)-Se(1) bond lengths are 2.48 Å. Se(1) is bonded to five equivalent Na(1) and two equivalent Zn(1) atoms to form distorted SeNa5Zn2 pentagonal bipyramids that share corners with eight equivalent Se(1)Na5Zn2 pentagonal bipyramids, corners with six equivalent Zn(1)Na4Se4 tetrahedra, edges with six equivalent Se(1)Na5Zn2 pentagonal bipyramids, edges with two equivalent Zn(1)Na4Se4 tetrahedra, and faces with two equivalent Se(1)Na5Zn2 pentagonal bipyramids.