Pu2Se3 crystallizes in the tetragonal I-42d space group. There are three inequivalent Pu sites. In the first Pu site, Pu(1) is bonded to two equivalent Se(1), three equivalent Se(2), and three equivalent Se(3) atoms to form a mixture of distorted corner, edge, and face-sharing PuSe8 hexagonal bipyramids. In the second Pu site, Pu(2) is bonded to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms to form a mixture of distorted corner, edge, and face-sharing PuSe8 hexagonal bipyramids. In the third Pu site, Pu(3) is bonded to two equivalent Se(2), two equivalent Se(3), and four equivalent Se(1) atoms to form a mixture of distorted corner, edge, and face-sharing PuSe8 hexagonal bipyramids. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Pu(2), two equivalent Pu(1), and two equivalent Pu(3) atoms to form SePu5 square pyramids that share corners with five equivalent Se(2)Pu6 octahedra, corners with four equivalent Se(1)Pu5 square pyramids, corners with four equivalent Se(3)Pu5 square pyramids, edges with three equivalent Se(2)Pu6 octahedra,  an edgeedge with one Se(1)Pu5 square pyramid, edges with four equivalent Se(3)Pu5 square pyramids,  a faceface with one Se(2)Pu6 octahedra, and  a faceface with one Se(1)Pu5 square pyramid. The corner-sharing octahedral tilt angles range from 19-49°. In the second Se site, Se(2) is bonded to one Pu(3), two equivalent Pu(2), and three equivalent Pu(1) atoms to form distorted SePu6 octahedra that share corners with three equivalent Se(2)Pu6 octahedra, corners with five equivalent Se(1)Pu5 square pyramids, corners with seven equivalent Se(3)Pu5 square pyramids, edges with two equivalent Se(2)Pu6 octahedra,  an edgeedge with one Se(3)Pu5 square pyramid, edges with three equivalent Se(1)Pu5 square pyramids, faces with two equivalent Se(2)Pu6 octahedra,  a faceface with one Se(1)Pu5 square pyramid, and faces with two equivalent Se(3)Pu5 square pyramids. The corner-sharing octahedral tilt angles range from 17-50°. In the third Se site, Se(3) is bonded to one Pu(2), one Pu(3), and three equivalent Pu(1) atoms to form distorted SePu5 square pyramids that share corners with seven equivalent Se(2)Pu6 octahedra, corners with four equivalent Se(1)Pu5 square pyramids, corners with five equivalent Se(3)Pu5 square pyramids,  an edgeedge with one Se(2)Pu6 octahedra, edges with four equivalent Se(1)Pu5 square pyramids, faces with two equivalent Se(2)Pu6 octahedra, and  a faceface with one Se(3)Pu5 square pyramid. The corner-sharing octahedral tilt angles range from 14-53°.
Pu2Se3 crystallizes in the tetragonal I-42d space group. There are three inequivalent Pu sites. In the first Pu site, Pu(1) is bonded to two equivalent Se(1), three equivalent Se(2), and three equivalent Se(3) atoms to form a mixture of distorted corner, edge, and face-sharing PuSe8 hexagonal bipyramids. There is one shorter (2.93 Å) and one longer (3.10 Å) Pu(1)-Se(1) bond length. There are a spread of Pu(1)-Se(2) bond distances ranging from 2.94-3.16 Å. There are a spread of Pu(1)-Se(3) bond distances ranging from 2.90-3.08 Å. In the second Pu site, Pu(2) is bonded to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms to form a mixture of distorted corner, edge, and face-sharing PuSe8 hexagonal bipyramids. Both Pu(2)-Se(1) bond lengths are 2.92 Å. Both Pu(2)-Se(3) bond lengths are 3.10 Å. There are two shorter (2.95 Å) and two longer (3.08 Å) Pu(2)-Se(2) bond lengths. In the third Pu site, Pu(3) is bonded to two equivalent Se(2), two equivalent Se(3), and four equivalent Se(1) atoms to form a mixture of distorted corner, edge, and face-sharing PuSe8 hexagonal bipyramids. Both Pu(3)-Se(2) bond lengths are 3.12 Å. Both Pu(3)-Se(3) bond lengths are 2.97 Å. There are two shorter (2.94 Å) and two longer (3.07 Å) Pu(3)-Se(1) bond lengths. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Pu(2), two equivalent Pu(1), and two equivalent Pu(3) atoms to form SePu5 square pyramids that share corners with five equivalent Se(2)Pu6 octahedra, corners with four equivalent Se(1)Pu5 square pyramids, corners with four equivalent Se(3)Pu5 square pyramids, edges with three equivalent Se(2)Pu6 octahedra,  an edgeedge with one Se(1)Pu5 square pyramid, edges with four equivalent Se(3)Pu5 square pyramids,  a faceface with one Se(2)Pu6 octahedra, and  a faceface with one Se(1)Pu5 square pyramid. The corner-sharing octahedral tilt angles range from 19-49°. In the second Se site, Se(2) is bonded to one Pu(3), two equivalent Pu(2), and three equivalent Pu(1) atoms to form distorted SePu6 octahedra that share corners with three equivalent Se(2)Pu6 octahedra, corners with five equivalent Se(1)Pu5 square pyramids, corners with seven equivalent Se(3)Pu5 square pyramids, edges with two equivalent Se(2)Pu6 octahedra,  an edgeedge with one Se(3)Pu5 square pyramid, edges with three equivalent Se(1)Pu5 square pyramids, faces with two equivalent Se(2)Pu6 octahedra,  a faceface with one Se(1)Pu5 square pyramid, and faces with two equivalent Se(3)Pu5 square pyramids. The corner-sharing octahedral tilt angles range from 17-50°. In the third Se site, Se(3) is bonded to one Pu(2), one Pu(3), and three equivalent Pu(1) atoms to form distorted SePu5 square pyramids that share corners with seven equivalent Se(2)Pu6 octahedra, corners with four equivalent Se(1)Pu5 square pyramids, corners with five equivalent Se(3)Pu5 square pyramids,  an edgeedge with one Se(2)Pu6 octahedra, edges with four equivalent Se(1)Pu5 square pyramids, faces with two equivalent Se(2)Pu6 octahedra, and  a faceface with one Se(3)Pu5 square pyramid. The corner-sharing octahedral tilt angles range from 14-53°.