NaCuHf2Se5 crystallizes in the orthorhombic Cmcm space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent Se(2) and four equivalent Se(3) atoms. Hf(1) is bonded to one Se(2), two equivalent Se(3), and three equivalent Se(1) atoms to form distorted HfSe6 octahedra that share  a cornercorner with one Hf(1)Se6 octahedra, edges with four equivalent Hf(1)Se6 octahedra, and edges with two equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. Cu(1) is bonded to two equivalent Se(2) and two equivalent Se(3) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra and edges with four equivalent Hf(1)Se6 octahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to three equivalent Hf(1) atoms. In the second Se site, Se(2) is bonded to two equivalent Na(1), two equivalent Hf(1), and two equivalent Cu(1) atoms to form distorted edge-sharing SeNa2Hf2Cu2 octahedra. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Hf(1), and one Cu(1) atom.
NaCuHf2Se5 crystallizes in the orthorhombic Cmcm space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent Se(2) and four equivalent Se(3) atoms. Both Na(1)-Se(2) bond lengths are 3.09 Å. All Na(1)-Se(3) bond lengths are 3.16 Å. Hf(1) is bonded to one Se(2), two equivalent Se(3), and three equivalent Se(1) atoms to form distorted HfSe6 octahedra that share  a cornercorner with one Hf(1)Se6 octahedra, edges with four equivalent Hf(1)Se6 octahedra, and edges with two equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. The Hf(1)-Se(2) bond length is 2.72 Å. Both Hf(1)-Se(3) bond lengths are 2.68 Å. There is one shorter (2.68 Å) and two longer (2.70 Å) Hf(1)-Se(1) bond lengths. Cu(1) is bonded to two equivalent Se(2) and two equivalent Se(3) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra and edges with four equivalent Hf(1)Se6 octahedra. Both Cu(1)-Se(2) bond lengths are 2.47 Å. Both Cu(1)-Se(3) bond lengths are 2.42 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to three equivalent Hf(1) atoms. In the second Se site, Se(2) is bonded to two equivalent Na(1), two equivalent Hf(1), and two equivalent Cu(1) atoms to form distorted edge-sharing SeNa2Hf2Cu2 octahedra. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Hf(1), and one Cu(1) atom.