Hf23Se25 crystallizes in the triclinic P1 space group. There are twenty-three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one Se(1), one Se(2), one Se(25), one Se(3), one Se(5), and one Se(7) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the second Hf site, Hf(2) is bonded to one Se(1), one Se(10), one Se(2), one Se(4), one Se(5), and one Se(6) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the third Hf site, Hf(3) is bonded to one Se(10), one Se(11), one Se(3), one Se(6), one Se(7), and one Se(8) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the fourth Hf site, Hf(4) is bonded to one Se(1), one Se(2), one Se(3), one Se(4), one Se(7), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the fifth Hf site, Hf(5) is bonded to one Se(1), one Se(10), one Se(23), one Se(25), one Se(4), and one Se(5) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the sixth Hf site, Hf(6) is bonded to one Se(10), one Se(12), one Se(14), one Se(3), one Se(6), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the seventh Hf site, Hf(7) is bonded to one Se(10), one Se(11), one Se(2), one Se(4), one Se(6), and one Se(7) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the eighth Hf site, Hf(8) is bonded to one Se(11), one Se(15), one Se(3), one Se(6), one Se(8), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the ninth Hf site, Hf(9) is bonded to one Se(10), one Se(14), one Se(3), one Se(4), one Se(7), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the tenth Hf site, Hf(10) is bonded to one Se(12), one Se(14), one Se(15), one Se(17), one Se(20), and one Se(8) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the eleventh Hf site, Hf(11) is bonded to one Se(11), one Se(12), one Se(14), one Se(16), one Se(6), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the twelfth Hf site, Hf(12) is bonded to one Se(13), one Se(16), one Se(17), one Se(18), one Se(20), and one Se(21) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the thirteenth Hf site, Hf(13) is bonded to one Se(12), one Se(13), one Se(15), one Se(16), one Se(19), and one Se(8) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the fourteenth Hf site, Hf(14) is bonded to one Se(11), one Se(14), one Se(15), one Se(20), one Se(8), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the fifteenth Hf site, Hf(15) is bonded to one Se(12), one Se(15), one Se(16), one Se(17), one Se(20), and one Se(21) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the sixteenth Hf site, Hf(16) is bonded to one Se(13), one Se(17), one Se(19), one Se(20), one Se(22), and one Se(24) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the seventeenth Hf site, Hf(17) is bonded to one Se(13), one Se(17), one Se(18), one Se(19), one Se(21), and one Se(23) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the eighteenth Hf site, Hf(18) is bonded to one Se(13), one Se(15), one Se(16), one Se(19), one Se(20), and one Se(24) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the nineteenth Hf site, Hf(19) is bonded to one Se(1), one Se(18), one Se(21), one Se(22), one Se(24), and one Se(25) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the twentieth Hf site, Hf(20) is bonded to one Se(18), one Se(2), one Se(22), one Se(23), one Se(24), and one Se(5) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the twenty-first Hf site, Hf(21) is bonded to one Se(17), one Se(19), one Se(21), one Se(22), one Se(24), and one Se(25) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the twenty-second Hf site, Hf(22) is bonded to one Se(18), one Se(19), one Se(21), one Se(23), one Se(24), and one Se(5) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. In the twenty-third Hf site, Hf(23) is bonded to one Se(1), one Se(18), one Se(22), one Se(23), one Se(25), and one Se(4) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. There are twenty-five inequivalent Se sites. In the first Se site, Se(1) is bonded to one Hf(1), one Hf(19), one Hf(2), one Hf(23), one Hf(4), and one Hf(5) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid,  an edgeedge with one Se(10)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(3)Hf6 pentagonal pyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid,  an edgeedge with one Se(5)Hf5 trigonal bipyramid,  a faceface with one Se(4)Hf6 pentagonal pyramid, and  a faceface with one Se(25)Hf5 trigonal bipyramid. In the second Se site, Se(2) is bonded in a distorted pentagonal planar geometry to one Hf(1), one Hf(2), one Hf(20), one Hf(4), and one Hf(7) atom. In the third Se site, Se(3) is bonded to one Hf(1), one Hf(3), one Hf(4), one Hf(6), one Hf(8), and one Hf(9) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid, corners with two equivalent Se(4)Hf6 pentagonal pyramids,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid, corners with two equivalent Se(11)Hf5 trigonal bipyramids,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(10)Hf6 pentagonal pyramid,  an edgeedge with one Se(6)Hf6 pentagonal pyramid,  an edgeedge with one Se(8)Hf5 trigonal bipyramid, and  a faceface with one Se(9)Hf6 pentagonal pyramid. In the fourth Se site, Se(4) is bonded to one Hf(2), one Hf(23), one Hf(4), one Hf(5), one Hf(7), and one Hf(9) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(18)Hf6 pentagonal pyramid, corners with two equivalent Se(3)Hf6 pentagonal pyramids,  a cornercorner with one Se(11)Hf5 trigonal bipyramid,  a cornercorner with one Se(22)Hf5 trigonal bipyramid, corners with two equivalent Se(5)Hf5 trigonal bipyramids,  an edgeedge with one Se(6)Hf6 pentagonal pyramid,  an edgeedge with one Se(9)Hf6 pentagonal pyramid,  an edgeedge with one Se(25)Hf5 trigonal bipyramid,  a faceface with one Se(1)Hf6 pentagonal pyramid, and  a faceface with one Se(10)Hf6 pentagonal pyramid. In the fifth Se site, Se(5) is bonded to one Hf(1), one Hf(2), one Hf(20), one Hf(22), and one Hf(5) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid, corners with two equivalent Se(4)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid, corners with two equivalent Se(25)Hf5 trigonal bipyramids,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(10)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid, and  an edgeedge with one Se(24)Hf6 pentagonal pyramid. In the sixth Se site, Se(6) is bonded to one Hf(11), one Hf(2), one Hf(3), one Hf(6), one Hf(7), and one Hf(8) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid,  a cornercorner with one Se(11)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid,  an edgeedge with one Se(3)Hf6 pentagonal pyramid,  an edgeedge with one Se(4)Hf6 pentagonal pyramid,  an edgeedge with one Se(9)Hf6 pentagonal pyramid,  an edgeedge with one Se(8)Hf5 trigonal bipyramid,  a faceface with one Se(10)Hf6 pentagonal pyramid, and  a faceface with one Se(11)Hf5 trigonal bipyramid. In the seventh Se site, Se(7) is bonded in a distorted pentagonal planar geometry to one Hf(1), one Hf(3), one Hf(4), one Hf(7), and one Hf(9) atom. In the eighth Se site, Se(8) is bonded to one Hf(10), one Hf(13), one Hf(14), one Hf(3), and one Hf(8) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid, corners with two equivalent Se(9)Hf6 pentagonal pyramids,  a cornercorner with one Se(11)Hf5 trigonal bipyramid,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(20)Hf6 pentagonal pyramid,  an edgeedge with one Se(3)Hf6 pentagonal pyramid,  an edgeedge with one Se(6)Hf6 pentagonal pyramid,  an edgeedge with one Se(11)Hf5 trigonal bipyramid, and  a faceface with one Se(15)Hf6 pentagonal pyramid. In the ninth Se site, Se(9) is bonded to one Hf(11), one Hf(14), one Hf(4), one Hf(6), one Hf(8), and one Hf(9) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid, corners with two equivalent Se(10)Hf6 pentagonal pyramids,  a cornercorner with one Se(11)Hf5 trigonal bipyramid, corners with two equivalent Se(8)Hf5 trigonal bipyramids,  an edgeedge with one Se(15)Hf6 pentagonal pyramid,  an edgeedge with one Se(4)Hf6 pentagonal pyramid,  an edgeedge with one Se(6)Hf6 pentagonal pyramid,  an edgeedge with one Se(11)Hf5 trigonal bipyramid, and  a faceface with one Se(3)Hf6 pentagonal pyramid. In the tenth Se site, Se(10) is bonded to one Hf(2), one Hf(3), one Hf(5), one Hf(6), one Hf(7), and one Hf(9) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid, corners with two equivalent Se(9)Hf6 pentagonal pyramids,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(3)Hf6 pentagonal pyramid,  an edgeedge with one Se(11)Hf5 trigonal bipyramid,  an edgeedge with one Se(5)Hf5 trigonal bipyramid,  a faceface with one Se(4)Hf6 pentagonal pyramid, and  a faceface with one Se(6)Hf6 pentagonal pyramid. In the eleventh Se site, Se(11) is bonded to one Hf(11), one Hf(14), one Hf(3), one Hf(7), and one Hf(8) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid, corners with two equivalent Se(3)Hf6 pentagonal pyramids,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(10)Hf6 pentagonal pyramid,  an edgeedge with one Se(15)Hf6 pentagonal pyramid,  an edgeedge with one Se(9)Hf6 pentagonal pyramid,  an edgeedge with one Se(8)Hf5 trigonal bipyramid, and  a faceface with one Se(6)Hf6 pentagonal pyramid. In the twelfth Se site, Se(12) is bonded in a distorted pentagonal planar geometry to one Hf(10), one Hf(11), one Hf(13), one Hf(15), and one Hf(6) atom. In the thirteenth Se site, Se(13) is bonded to one Hf(12), one Hf(13), one Hf(16), one Hf(17), and one Hf(18) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(20)Hf6 pentagonal pyramid, corners with two equivalent Se(15)Hf6 pentagonal pyramids, corners with two equivalent Se(21)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(20)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid, and  a faceface with one Se(19)Hf6 pentagonal pyramid. In the fourteenth Se site, Se(14) is bonded in a distorted pentagonal planar geometry to one Hf(10), one Hf(11), one Hf(14), one Hf(6), and one Hf(9) atom. In the fifteenth Se site, Se(15) is bonded to one Hf(10), one Hf(13), one Hf(14), one Hf(15), one Hf(18), and one Hf(8) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid, corners with two equivalent Se(13)Hf5 trigonal bipyramids,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(19)Hf6 pentagonal pyramid,  an edgeedge with one Se(9)Hf6 pentagonal pyramid,  an edgeedge with one Se(11)Hf5 trigonal bipyramid,  a faceface with one Se(20)Hf6 pentagonal pyramid, and  a faceface with one Se(8)Hf5 trigonal bipyramid. In the sixteenth Se site, Se(16) is bonded in a distorted pentagonal planar geometry to one Hf(11), one Hf(12), one Hf(13), one Hf(15), and one Hf(18) atom. In the seventeenth Se site, Se(17) is bonded to one Hf(10), one Hf(12), one Hf(15), one Hf(16), one Hf(17), and one Hf(21) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid, corners with two equivalent Se(24)Hf6 pentagonal pyramids,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(15)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(19)Hf6 pentagonal pyramid,  an edgeedge with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid,  a faceface with one Se(20)Hf6 pentagonal pyramid, and  a faceface with one Se(21)Hf6 pentagonal pyramid. In the eighteenth Se site, Se(18) is bonded to one Hf(12), one Hf(17), one Hf(19), one Hf(20), one Hf(22), and one Hf(23) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid, corners with two equivalent Se(19)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid, corners with two equivalent Se(25)Hf5 trigonal bipyramids,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid,  an edgeedge with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid,  an edgeedge with one Se(5)Hf5 trigonal bipyramid, and  a faceface with one Se(21)Hf6 pentagonal pyramid. In the nineteenth Se site, Se(19) is bonded to one Hf(13), one Hf(16), one Hf(17), one Hf(18), one Hf(21), and one Hf(22) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid, corners with two equivalent Se(18)Hf6 pentagonal pyramids, corners with two equivalent Se(20)Hf6 pentagonal pyramids,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(15)Hf6 pentagonal pyramid,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(21)Hf6 pentagonal pyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid,  a faceface with one Se(24)Hf6 pentagonal pyramid, and  a faceface with one Se(13)Hf5 trigonal bipyramid. In the twentieth Se site, Se(20) is bonded to one Hf(10), one Hf(12), one Hf(14), one Hf(15), one Hf(16), and one Hf(18) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(18)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid, corners with two equivalent Se(19)Hf6 pentagonal pyramids,  a cornercorner with one Se(11)Hf5 trigonal bipyramid,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  a cornercorner with one Se(22)Hf5 trigonal bipyramid,  an edgeedge with one Se(21)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid,  an edgeedge with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(8)Hf5 trigonal bipyramid,  a faceface with one Se(15)Hf6 pentagonal pyramid, and  a faceface with one Se(17)Hf6 pentagonal pyramid. In the twenty-first Se site, Se(21) is bonded to one Hf(12), one Hf(15), one Hf(17), one Hf(19), one Hf(21), and one Hf(22) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(18)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid, corners with two equivalent Se(13)Hf5 trigonal bipyramids, corners with two equivalent Se(22)Hf5 trigonal bipyramids,  an edgeedge with one Se(19)Hf6 pentagonal pyramid,  an edgeedge with one Se(20)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid,  an edgeedge with one Se(25)Hf5 trigonal bipyramid,  a faceface with one Se(17)Hf6 pentagonal pyramid, and  a faceface with one Se(18)Hf6 pentagonal pyramid. In the twenty-second Se site, Se(22) is bonded to one Hf(16), one Hf(19), one Hf(20), one Hf(21), and one Hf(23) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(18)Hf6 pentagonal pyramid,  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid, corners with two equivalent Se(21)Hf6 pentagonal pyramids,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(19)Hf6 pentagonal pyramid,  an edgeedge with one Se(25)Hf5 trigonal bipyramid, and  a faceface with one Se(24)Hf6 pentagonal pyramid. In the twenty-third Se site, Se(23) is bonded in a distorted pentagonal planar geometry to one Hf(17), one Hf(20), one Hf(22), one Hf(23), and one Hf(5) atom. In the twenty-fourth Se site, Se(24) is bonded to one Hf(16), one Hf(18), one Hf(19), one Hf(20), one Hf(21), and one Hf(22) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(18)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid, corners with two equivalent Se(17)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(20)Hf6 pentagonal pyramid,  an edgeedge with one Se(21)Hf6 pentagonal pyramid,  an edgeedge with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(25)Hf5 trigonal bipyramid,  an edgeedge with one Se(5)Hf5 trigonal bipyramid,  a faceface with one Se(19)Hf6 pentagonal pyramid, and  a faceface with one Se(22)Hf5 trigonal bipyramid. In the twenty-fifth Se site, Se(25) is bonded to one Hf(1), one Hf(19), one Hf(21), one Hf(23), and one Hf(5) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid, corners with two equivalent Se(18)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid, corners with two equivalent Se(5)Hf5 trigonal bipyramids,  an edgeedge with one Se(21)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid,  an edgeedge with one Se(4)Hf6 pentagonal pyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid, and  a faceface with one Se(1)Hf6 pentagonal pyramid.
Hf23Se25 crystallizes in the triclinic P1 space group. There are twenty-three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one Se(1), one Se(2), one Se(25), one Se(3), one Se(5), and one Se(7) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(1)-Se(1) bond length is 2.74 Å. The Hf(1)-Se(2) bond length is 2.71 Å. The Hf(1)-Se(25) bond length is 2.70 Å. The Hf(1)-Se(3) bond length is 2.71 Å. The Hf(1)-Se(5) bond length is 2.68 Å. The Hf(1)-Se(7) bond length is 2.69 Å. In the second Hf site, Hf(2) is bonded to one Se(1), one Se(10), one Se(2), one Se(4), one Se(5), and one Se(6) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(2)-Se(1) bond length is 2.72 Å. The Hf(2)-Se(10) bond length is 2.73 Å. The Hf(2)-Se(2) bond length is 2.70 Å. The Hf(2)-Se(4) bond length is 2.73 Å. The Hf(2)-Se(5) bond length is 2.69 Å. The Hf(2)-Se(6) bond length is 2.72 Å. In the third Hf site, Hf(3) is bonded to one Se(10), one Se(11), one Se(3), one Se(6), one Se(7), and one Se(8) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(3)-Se(10) bond length is 2.73 Å. The Hf(3)-Se(11) bond length is 2.71 Å. The Hf(3)-Se(3) bond length is 2.68 Å. The Hf(3)-Se(6) bond length is 2.74 Å. The Hf(3)-Se(7) bond length is 2.68 Å. The Hf(3)-Se(8) bond length is 2.73 Å. In the fourth Hf site, Hf(4) is bonded to one Se(1), one Se(2), one Se(3), one Se(4), one Se(7), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(4)-Se(1) bond length is 2.70 Å. The Hf(4)-Se(2) bond length is 2.72 Å. The Hf(4)-Se(3) bond length is 2.68 Å. The Hf(4)-Se(4) bond length is 2.76 Å. The Hf(4)-Se(7) bond length is 2.71 Å. The Hf(4)-Se(9) bond length is 2.68 Å. In the fifth Hf site, Hf(5) is bonded to one Se(1), one Se(10), one Se(23), one Se(25), one Se(4), and one Se(5) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(5)-Se(1) bond length is 2.71 Å. The Hf(5)-Se(10) bond length is 2.76 Å. The Hf(5)-Se(23) bond length is 2.72 Å. The Hf(5)-Se(25) bond length is 2.68 Å. The Hf(5)-Se(4) bond length is 2.74 Å. The Hf(5)-Se(5) bond length is 2.72 Å. In the sixth Hf site, Hf(6) is bonded to one Se(10), one Se(12), one Se(14), one Se(3), one Se(6), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(6)-Se(10) bond length is 2.75 Å. The Hf(6)-Se(12) bond length is 2.72 Å. The Hf(6)-Se(14) bond length is 2.71 Å. The Hf(6)-Se(3) bond length is 2.69 Å. The Hf(6)-Se(6) bond length is 2.70 Å. The Hf(6)-Se(9) bond length is 2.68 Å. In the seventh Hf site, Hf(7) is bonded to one Se(10), one Se(11), one Se(2), one Se(4), one Se(6), and one Se(7) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(7)-Se(10) bond length is 2.73 Å. The Hf(7)-Se(11) bond length is 2.68 Å. The Hf(7)-Se(2) bond length is 2.72 Å. The Hf(7)-Se(4) bond length is 2.76 Å. The Hf(7)-Se(6) bond length is 2.70 Å. The Hf(7)-Se(7) bond length is 2.72 Å. In the eighth Hf site, Hf(8) is bonded to one Se(11), one Se(15), one Se(3), one Se(6), one Se(8), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(8)-Se(11) bond length is 2.72 Å. The Hf(8)-Se(15) bond length is 2.73 Å. The Hf(8)-Se(3) bond length is 2.71 Å. The Hf(8)-Se(6) bond length is 2.72 Å. The Hf(8)-Se(8) bond length is 2.72 Å. The Hf(8)-Se(9) bond length is 2.71 Å. In the ninth Hf site, Hf(9) is bonded to one Se(10), one Se(14), one Se(3), one Se(4), one Se(7), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(9)-Se(10) bond length is 2.74 Å. The Hf(9)-Se(14) bond length is 2.71 Å. The Hf(9)-Se(3) bond length is 2.69 Å. The Hf(9)-Se(4) bond length is 2.74 Å. The Hf(9)-Se(7) bond length is 2.71 Å. The Hf(9)-Se(9) bond length is 2.69 Å. In the tenth Hf site, Hf(10) is bonded to one Se(12), one Se(14), one Se(15), one Se(17), one Se(20), and one Se(8) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(10)-Se(12) bond length is 2.72 Å. The Hf(10)-Se(14) bond length is 2.72 Å. The Hf(10)-Se(15) bond length is 2.70 Å. The Hf(10)-Se(17) bond length is 2.73 Å. The Hf(10)-Se(20) bond length is 2.75 Å. The Hf(10)-Se(8) bond length is 2.68 Å. In the eleventh Hf site, Hf(11) is bonded to one Se(11), one Se(12), one Se(14), one Se(16), one Se(6), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(11)-Se(11) bond length is 2.69 Å. The Hf(11)-Se(12) bond length is 2.71 Å. The Hf(11)-Se(14) bond length is 2.69 Å. The Hf(11)-Se(16) bond length is 2.68 Å. The Hf(11)-Se(6) bond length is 2.74 Å. The Hf(11)-Se(9) bond length is 2.70 Å. In the twelfth Hf site, Hf(12) is bonded to one Se(13), one Se(16), one Se(17), one Se(18), one Se(20), and one Se(21) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(12)-Se(13) bond length is 2.72 Å. The Hf(12)-Se(16) bond length is 2.71 Å. The Hf(12)-Se(17) bond length is 2.73 Å. The Hf(12)-Se(18) bond length is 2.68 Å. The Hf(12)-Se(20) bond length is 2.75 Å. The Hf(12)-Se(21) bond length is 2.68 Å. In the thirteenth Hf site, Hf(13) is bonded to one Se(12), one Se(13), one Se(15), one Se(16), one Se(19), and one Se(8) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(13)-Se(12) bond length is 2.69 Å. The Hf(13)-Se(13) bond length is 2.69 Å. The Hf(13)-Se(15) bond length is 2.74 Å. The Hf(13)-Se(16) bond length is 2.71 Å. The Hf(13)-Se(19) bond length is 2.73 Å. The Hf(13)-Se(8) bond length is 2.70 Å. In the fourteenth Hf site, Hf(14) is bonded to one Se(11), one Se(14), one Se(15), one Se(20), one Se(8), and one Se(9) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(14)-Se(11) bond length is 2.72 Å. The Hf(14)-Se(14) bond length is 2.68 Å. The Hf(14)-Se(15) bond length is 2.74 Å. The Hf(14)-Se(20) bond length is 2.73 Å. The Hf(14)-Se(8) bond length is 2.71 Å. The Hf(14)-Se(9) bond length is 2.68 Å. In the fifteenth Hf site, Hf(15) is bonded to one Se(12), one Se(15), one Se(16), one Se(17), one Se(20), and one Se(21) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(15)-Se(12) bond length is 2.70 Å. The Hf(15)-Se(15) bond length is 2.72 Å. The Hf(15)-Se(16) bond length is 2.70 Å. The Hf(15)-Se(17) bond length is 2.73 Å. The Hf(15)-Se(20) bond length is 2.73 Å. The Hf(15)-Se(21) bond length is 2.71 Å. In the sixteenth Hf site, Hf(16) is bonded to one Se(13), one Se(17), one Se(19), one Se(20), one Se(22), and one Se(24) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(16)-Se(13) bond length is 2.72 Å. The Hf(16)-Se(17) bond length is 2.71 Å. The Hf(16)-Se(19) bond length is 2.71 Å. The Hf(16)-Se(20) bond length is 2.72 Å. The Hf(16)-Se(22) bond length is 2.70 Å. The Hf(16)-Se(24) bond length is 2.72 Å. In the seventeenth Hf site, Hf(17) is bonded to one Se(13), one Se(17), one Se(18), one Se(19), one Se(21), and one Se(23) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(17)-Se(13) bond length is 2.72 Å. The Hf(17)-Se(17) bond length is 2.73 Å. The Hf(17)-Se(18) bond length is 2.68 Å. The Hf(17)-Se(19) bond length is 2.72 Å. The Hf(17)-Se(21) bond length is 2.71 Å. The Hf(17)-Se(23) bond length is 2.72 Å. In the eighteenth Hf site, Hf(18) is bonded to one Se(13), one Se(15), one Se(16), one Se(19), one Se(20), and one Se(24) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(18)-Se(13) bond length is 2.72 Å. The Hf(18)-Se(15) bond length is 2.71 Å. The Hf(18)-Se(16) bond length is 2.72 Å. The Hf(18)-Se(19) bond length is 2.69 Å. The Hf(18)-Se(20) bond length is 2.75 Å. The Hf(18)-Se(24) bond length is 2.68 Å. In the nineteenth Hf site, Hf(19) is bonded to one Se(1), one Se(18), one Se(21), one Se(22), one Se(24), and one Se(25) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(19)-Se(1) bond length is 2.72 Å. The Hf(19)-Se(18) bond length is 2.71 Å. The Hf(19)-Se(21) bond length is 2.72 Å. The Hf(19)-Se(22) bond length is 2.72 Å. The Hf(19)-Se(24) bond length is 2.71 Å. The Hf(19)-Se(25) bond length is 2.72 Å. In the twentieth Hf site, Hf(20) is bonded to one Se(18), one Se(2), one Se(22), one Se(23), one Se(24), and one Se(5) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(20)-Se(18) bond length is 2.71 Å. The Hf(20)-Se(2) bond length is 2.68 Å. The Hf(20)-Se(22) bond length is 2.69 Å. The Hf(20)-Se(23) bond length is 2.69 Å. The Hf(20)-Se(24) bond length is 2.73 Å. The Hf(20)-Se(5) bond length is 2.71 Å. In the twenty-first Hf site, Hf(21) is bonded to one Se(17), one Se(19), one Se(21), one Se(22), one Se(24), and one Se(25) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(21)-Se(17) bond length is 2.72 Å. The Hf(21)-Se(19) bond length is 2.71 Å. The Hf(21)-Se(21) bond length is 2.68 Å. The Hf(21)-Se(22) bond length is 2.72 Å. The Hf(21)-Se(24) bond length is 2.72 Å. The Hf(21)-Se(25) bond length is 2.72 Å. In the twenty-second Hf site, Hf(22) is bonded to one Se(18), one Se(19), one Se(21), one Se(23), one Se(24), and one Se(5) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(22)-Se(18) bond length is 2.68 Å. The Hf(22)-Se(19) bond length is 2.72 Å. The Hf(22)-Se(21) bond length is 2.69 Å. The Hf(22)-Se(23) bond length is 2.72 Å. The Hf(22)-Se(24) bond length is 2.70 Å. The Hf(22)-Se(5) bond length is 2.73 Å. In the twenty-third Hf site, Hf(23) is bonded to one Se(1), one Se(18), one Se(22), one Se(23), one Se(25), and one Se(4) atom to form a mixture of distorted edge, face, and corner-sharing HfSe6 pentagonal pyramids. The Hf(23)-Se(1) bond length is 2.74 Å. The Hf(23)-Se(18) bond length is 2.67 Å. The Hf(23)-Se(22) bond length is 2.73 Å. The Hf(23)-Se(23) bond length is 2.68 Å. The Hf(23)-Se(25) bond length is 2.71 Å. The Hf(23)-Se(4) bond length is 2.75 Å. There are twenty-five inequivalent Se sites. In the first Se site, Se(1) is bonded to one Hf(1), one Hf(19), one Hf(2), one Hf(23), one Hf(4), and one Hf(5) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid,  an edgeedge with one Se(10)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(3)Hf6 pentagonal pyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid,  an edgeedge with one Se(5)Hf5 trigonal bipyramid,  a faceface with one Se(4)Hf6 pentagonal pyramid, and  a faceface with one Se(25)Hf5 trigonal bipyramid. In the second Se site, Se(2) is bonded in a distorted pentagonal planar geometry to one Hf(1), one Hf(2), one Hf(20), one Hf(4), and one Hf(7) atom. In the third Se site, Se(3) is bonded to one Hf(1), one Hf(3), one Hf(4), one Hf(6), one Hf(8), and one Hf(9) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid, corners with two equivalent Se(4)Hf6 pentagonal pyramids,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid, corners with two equivalent Se(11)Hf5 trigonal bipyramids,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(10)Hf6 pentagonal pyramid,  an edgeedge with one Se(6)Hf6 pentagonal pyramid,  an edgeedge with one Se(8)Hf5 trigonal bipyramid, and  a faceface with one Se(9)Hf6 pentagonal pyramid. In the fourth Se site, Se(4) is bonded to one Hf(2), one Hf(23), one Hf(4), one Hf(5), one Hf(7), and one Hf(9) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(18)Hf6 pentagonal pyramid, corners with two equivalent Se(3)Hf6 pentagonal pyramids,  a cornercorner with one Se(11)Hf5 trigonal bipyramid,  a cornercorner with one Se(22)Hf5 trigonal bipyramid, corners with two equivalent Se(5)Hf5 trigonal bipyramids,  an edgeedge with one Se(6)Hf6 pentagonal pyramid,  an edgeedge with one Se(9)Hf6 pentagonal pyramid,  an edgeedge with one Se(25)Hf5 trigonal bipyramid,  a faceface with one Se(1)Hf6 pentagonal pyramid, and  a faceface with one Se(10)Hf6 pentagonal pyramid. In the fifth Se site, Se(5) is bonded to one Hf(1), one Hf(2), one Hf(20), one Hf(22), and one Hf(5) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid, corners with two equivalent Se(4)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid, corners with two equivalent Se(25)Hf5 trigonal bipyramids,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(10)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid, and  an edgeedge with one Se(24)Hf6 pentagonal pyramid. In the sixth Se site, Se(6) is bonded to one Hf(11), one Hf(2), one Hf(3), one Hf(6), one Hf(7), and one Hf(8) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid,  a cornercorner with one Se(11)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid,  an edgeedge with one Se(3)Hf6 pentagonal pyramid,  an edgeedge with one Se(4)Hf6 pentagonal pyramid,  an edgeedge with one Se(9)Hf6 pentagonal pyramid,  an edgeedge with one Se(8)Hf5 trigonal bipyramid,  a faceface with one Se(10)Hf6 pentagonal pyramid, and  a faceface with one Se(11)Hf5 trigonal bipyramid. In the seventh Se site, Se(7) is bonded in a distorted pentagonal planar geometry to one Hf(1), one Hf(3), one Hf(4), one Hf(7), and one Hf(9) atom. In the eighth Se site, Se(8) is bonded to one Hf(10), one Hf(13), one Hf(14), one Hf(3), and one Hf(8) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid, corners with two equivalent Se(9)Hf6 pentagonal pyramids,  a cornercorner with one Se(11)Hf5 trigonal bipyramid,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(20)Hf6 pentagonal pyramid,  an edgeedge with one Se(3)Hf6 pentagonal pyramid,  an edgeedge with one Se(6)Hf6 pentagonal pyramid,  an edgeedge with one Se(11)Hf5 trigonal bipyramid, and  a faceface with one Se(15)Hf6 pentagonal pyramid. In the ninth Se site, Se(9) is bonded to one Hf(11), one Hf(14), one Hf(4), one Hf(6), one Hf(8), and one Hf(9) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid, corners with two equivalent Se(10)Hf6 pentagonal pyramids,  a cornercorner with one Se(11)Hf5 trigonal bipyramid, corners with two equivalent Se(8)Hf5 trigonal bipyramids,  an edgeedge with one Se(15)Hf6 pentagonal pyramid,  an edgeedge with one Se(4)Hf6 pentagonal pyramid,  an edgeedge with one Se(6)Hf6 pentagonal pyramid,  an edgeedge with one Se(11)Hf5 trigonal bipyramid, and  a faceface with one Se(3)Hf6 pentagonal pyramid. In the tenth Se site, Se(10) is bonded to one Hf(2), one Hf(3), one Hf(5), one Hf(6), one Hf(7), and one Hf(9) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid, corners with two equivalent Se(9)Hf6 pentagonal pyramids,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(3)Hf6 pentagonal pyramid,  an edgeedge with one Se(11)Hf5 trigonal bipyramid,  an edgeedge with one Se(5)Hf5 trigonal bipyramid,  a faceface with one Se(4)Hf6 pentagonal pyramid, and  a faceface with one Se(6)Hf6 pentagonal pyramid. In the eleventh Se site, Se(11) is bonded to one Hf(11), one Hf(14), one Hf(3), one Hf(7), and one Hf(8) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid, corners with two equivalent Se(3)Hf6 pentagonal pyramids,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(10)Hf6 pentagonal pyramid,  an edgeedge with one Se(15)Hf6 pentagonal pyramid,  an edgeedge with one Se(9)Hf6 pentagonal pyramid,  an edgeedge with one Se(8)Hf5 trigonal bipyramid, and  a faceface with one Se(6)Hf6 pentagonal pyramid. In the twelfth Se site, Se(12) is bonded in a distorted pentagonal planar geometry to one Hf(10), one Hf(11), one Hf(13), one Hf(15), and one Hf(6) atom. In the thirteenth Se site, Se(13) is bonded to one Hf(12), one Hf(13), one Hf(16), one Hf(17), and one Hf(18) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(20)Hf6 pentagonal pyramid, corners with two equivalent Se(15)Hf6 pentagonal pyramids, corners with two equivalent Se(21)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(20)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid, and  a faceface with one Se(19)Hf6 pentagonal pyramid. In the fourteenth Se site, Se(14) is bonded in a distorted pentagonal planar geometry to one Hf(10), one Hf(11), one Hf(14), one Hf(6), and one Hf(9) atom. In the fifteenth Se site, Se(15) is bonded to one Hf(10), one Hf(13), one Hf(14), one Hf(15), one Hf(18), and one Hf(8) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid,  a cornercorner with one Se(6)Hf6 pentagonal pyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid, corners with two equivalent Se(13)Hf5 trigonal bipyramids,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(19)Hf6 pentagonal pyramid,  an edgeedge with one Se(9)Hf6 pentagonal pyramid,  an edgeedge with one Se(11)Hf5 trigonal bipyramid,  a faceface with one Se(20)Hf6 pentagonal pyramid, and  a faceface with one Se(8)Hf5 trigonal bipyramid. In the sixteenth Se site, Se(16) is bonded in a distorted pentagonal planar geometry to one Hf(11), one Hf(12), one Hf(13), one Hf(15), and one Hf(18) atom. In the seventeenth Se site, Se(17) is bonded to one Hf(10), one Hf(12), one Hf(15), one Hf(16), one Hf(17), and one Hf(21) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid, corners with two equivalent Se(24)Hf6 pentagonal pyramids,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(15)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(19)Hf6 pentagonal pyramid,  an edgeedge with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid,  a faceface with one Se(20)Hf6 pentagonal pyramid, and  a faceface with one Se(21)Hf6 pentagonal pyramid. In the eighteenth Se site, Se(18) is bonded to one Hf(12), one Hf(17), one Hf(19), one Hf(20), one Hf(22), and one Hf(23) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid, corners with two equivalent Se(19)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid, corners with two equivalent Se(25)Hf5 trigonal bipyramids,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid,  an edgeedge with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid,  an edgeedge with one Se(5)Hf5 trigonal bipyramid, and  a faceface with one Se(21)Hf6 pentagonal pyramid. In the nineteenth Se site, Se(19) is bonded to one Hf(13), one Hf(16), one Hf(17), one Hf(18), one Hf(21), and one Hf(22) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid, corners with two equivalent Se(18)Hf6 pentagonal pyramids, corners with two equivalent Se(20)Hf6 pentagonal pyramids,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid,  a cornercorner with one Se(8)Hf5 trigonal bipyramid,  an edgeedge with one Se(15)Hf6 pentagonal pyramid,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(21)Hf6 pentagonal pyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid,  a faceface with one Se(24)Hf6 pentagonal pyramid, and  a faceface with one Se(13)Hf5 trigonal bipyramid. In the twentieth Se site, Se(20) is bonded to one Hf(10), one Hf(12), one Hf(14), one Hf(15), one Hf(16), and one Hf(18) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(18)Hf6 pentagonal pyramid,  a cornercorner with one Se(9)Hf6 pentagonal pyramid, corners with two equivalent Se(19)Hf6 pentagonal pyramids,  a cornercorner with one Se(11)Hf5 trigonal bipyramid,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  a cornercorner with one Se(22)Hf5 trigonal bipyramid,  an edgeedge with one Se(21)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid,  an edgeedge with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(8)Hf5 trigonal bipyramid,  a faceface with one Se(15)Hf6 pentagonal pyramid, and  a faceface with one Se(17)Hf6 pentagonal pyramid. In the twenty-first Se site, Se(21) is bonded to one Hf(12), one Hf(15), one Hf(17), one Hf(19), one Hf(21), and one Hf(22) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(18)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid, corners with two equivalent Se(13)Hf5 trigonal bipyramids, corners with two equivalent Se(22)Hf5 trigonal bipyramids,  an edgeedge with one Se(19)Hf6 pentagonal pyramid,  an edgeedge with one Se(20)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid,  an edgeedge with one Se(25)Hf5 trigonal bipyramid,  a faceface with one Se(17)Hf6 pentagonal pyramid, and  a faceface with one Se(18)Hf6 pentagonal pyramid. In the twenty-second Se site, Se(22) is bonded to one Hf(16), one Hf(19), one Hf(20), one Hf(21), and one Hf(23) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(18)Hf6 pentagonal pyramid,  a cornercorner with one Se(20)Hf6 pentagonal pyramid,  a cornercorner with one Se(24)Hf6 pentagonal pyramid,  a cornercorner with one Se(4)Hf6 pentagonal pyramid, corners with two equivalent Se(21)Hf6 pentagonal pyramids,  a cornercorner with one Se(13)Hf5 trigonal bipyramid,  a cornercorner with one Se(25)Hf5 trigonal bipyramid,  a cornercorner with one Se(5)Hf5 trigonal bipyramid,  an edgeedge with one Se(1)Hf6 pentagonal pyramid,  an edgeedge with one Se(17)Hf6 pentagonal pyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(19)Hf6 pentagonal pyramid,  an edgeedge with one Se(25)Hf5 trigonal bipyramid, and  a faceface with one Se(24)Hf6 pentagonal pyramid. In the twenty-third Se site, Se(23) is bonded in a distorted pentagonal planar geometry to one Hf(17), one Hf(20), one Hf(22), one Hf(23), and one Hf(5) atom. In the twenty-fourth Se site, Se(24) is bonded to one Hf(16), one Hf(18), one Hf(19), one Hf(20), one Hf(21), and one Hf(22) atom to form distorted SeHf6 pentagonal pyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(15)Hf6 pentagonal pyramid,  a cornercorner with one Se(18)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(21)Hf6 pentagonal pyramid, corners with two equivalent Se(17)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid,  an edgeedge with one Se(18)Hf6 pentagonal pyramid,  an edgeedge with one Se(20)Hf6 pentagonal pyramid,  an edgeedge with one Se(21)Hf6 pentagonal pyramid,  an edgeedge with one Se(13)Hf5 trigonal bipyramid,  an edgeedge with one Se(25)Hf5 trigonal bipyramid,  an edgeedge with one Se(5)Hf5 trigonal bipyramid,  a faceface with one Se(19)Hf6 pentagonal pyramid, and  a faceface with one Se(22)Hf5 trigonal bipyramid. In the twenty-fifth Se site, Se(25) is bonded to one Hf(1), one Hf(19), one Hf(21), one Hf(23), and one Hf(5) atom to form distorted SeHf5 trigonal bipyramids that share  a cornercorner with one Se(1)Hf6 pentagonal pyramid,  a cornercorner with one Se(10)Hf6 pentagonal pyramid,  a cornercorner with one Se(17)Hf6 pentagonal pyramid,  a cornercorner with one Se(19)Hf6 pentagonal pyramid,  a cornercorner with one Se(3)Hf6 pentagonal pyramid, corners with two equivalent Se(18)Hf6 pentagonal pyramids,  a cornercorner with one Se(22)Hf5 trigonal bipyramid, corners with two equivalent Se(5)Hf5 trigonal bipyramids,  an edgeedge with one Se(21)Hf6 pentagonal pyramid,  an edgeedge with one Se(24)Hf6 pentagonal pyramid,  an edgeedge with one Se(4)Hf6 pentagonal pyramid,  an edgeedge with one Se(22)Hf5 trigonal bipyramid, and  a faceface with one Se(1)Hf6 pentagonal pyramid.