Na3Fe2S4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form distorted NaS6 octahedra that share corners with eight equivalent Na(2)S5 square pyramids, corners with eight equivalent Fe(1)S4 tetrahedra, edges with two equivalent Na(2)S5 square pyramids, edges with two equivalent Fe(1)S4 tetrahedra, and faces with two equivalent Na(1)S6 octahedra. In the second Na site, Na(2) is bonded to one S(2), two equivalent S(1), and two equivalent S(3) atoms to form distorted NaS5 square pyramids that share corners with four equivalent Na(1)S6 octahedra, corners with two equivalent Na(2)S5 square pyramids, corners with six equivalent Fe(1)S4 tetrahedra,  an edgeedge with one Na(1)S6 octahedra, edges with two equivalent Na(2)S5 square pyramids, edges with two equivalent Fe(1)S4 tetrahedra, and  a faceface with one Na(2)S5 square pyramid. The corner-sharing octahedral tilt angles range from 35-82°. Fe(1) is bonded to one S(2), one S(3), and two equivalent S(1) atoms to form FeS4 tetrahedra that share corners with four equivalent Na(1)S6 octahedra, corners with six equivalent Na(2)S5 square pyramids,  an edgeedge with one Na(1)S6 octahedra, edges with two equivalent Na(2)S5 square pyramids, and edges with two equivalent Fe(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 15-66°. There are three inequivalent S sites. In the first S site, S(3) is bonded to four equivalent Na(2) and two equivalent Fe(1) atoms to form distorted edge-sharing SNa4Fe2 pentagonal pyramids. In the second S site, S(1) is bonded in a 6-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and two equivalent Fe(1) atoms. In the third S site, S(2) is bonded in a 6-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and two equivalent Fe(1) atoms.
Na3Fe2S4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form distorted NaS6 octahedra that share corners with eight equivalent Na(2)S5 square pyramids, corners with eight equivalent Fe(1)S4 tetrahedra, edges with two equivalent Na(2)S5 square pyramids, edges with two equivalent Fe(1)S4 tetrahedra, and faces with two equivalent Na(1)S6 octahedra. There is one shorter (2.80 Å) and one longer (2.85 Å) Na(1)-S(2) bond length. There are two shorter (2.93 Å) and two longer (3.06 Å) Na(1)-S(1) bond lengths. In the second Na site, Na(2) is bonded to one S(2), two equivalent S(1), and two equivalent S(3) atoms to form distorted NaS5 square pyramids that share corners with four equivalent Na(1)S6 octahedra, corners with two equivalent Na(2)S5 square pyramids, corners with six equivalent Fe(1)S4 tetrahedra,  an edgeedge with one Na(1)S6 octahedra, edges with two equivalent Na(2)S5 square pyramids, edges with two equivalent Fe(1)S4 tetrahedra, and  a faceface with one Na(2)S5 square pyramid. The corner-sharing octahedral tilt angles range from 35-82°. The Na(2)-S(2) bond length is 3.05 Å. There is one shorter (2.91 Å) and one longer (3.00 Å) Na(2)-S(1) bond length. There is one shorter (2.83 Å) and one longer (2.91 Å) Na(2)-S(3) bond length. Fe(1) is bonded to one S(2), one S(3), and two equivalent S(1) atoms to form FeS4 tetrahedra that share corners with four equivalent Na(1)S6 octahedra, corners with six equivalent Na(2)S5 square pyramids,  an edgeedge with one Na(1)S6 octahedra, edges with two equivalent Na(2)S5 square pyramids, and edges with two equivalent Fe(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 15-66°. The Fe(1)-S(2) bond length is 2.28 Å. The Fe(1)-S(3) bond length is 2.25 Å. There is one shorter (2.26 Å) and one longer (2.29 Å) Fe(1)-S(1) bond length. There are three inequivalent S sites. In the first S site, S(3) is bonded to four equivalent Na(2) and two equivalent Fe(1) atoms to form distorted edge-sharing SNa4Fe2 pentagonal pyramids. In the second S site, S(1) is bonded in a 6-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and two equivalent Fe(1) atoms. In the third S site, S(2) is bonded in a 6-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and two equivalent Fe(1) atoms.