V2Pb5SiO12 crystallizes in the monoclinic Pm space group. There are four inequivalent V sites. In the first V site, V(1) is bonded to one O(15), one O(9), and two equivalent O(3) atoms to form VO4 tetrahedra that share  a cornercorner with one Pb(1)O5 trigonal bipyramid and  an edgeedge with one Pb(3)O6 pentagonal pyramid. In the second V site, V(2) is bonded to one O(10), one O(16), and two equivalent O(4) atoms to form VO4 tetrahedra that share  a cornercorner with one Pb(6)O6 pentagonal pyramid and corners with two equivalent Pb(2)O5 trigonal bipyramids. In the third V site, V(3) is bonded to one O(11), one O(17), and two equivalent O(5) atoms to form VO4 tetrahedra that share  a cornercorner with one Pb(6)O6 pentagonal pyramid and corners with two equivalent Pb(3)O6 pentagonal pyramids. In the fourth V site, V(4) is bonded to one O(12), one O(18), and two equivalent O(6) atoms to form VO4 tetrahedra that share corners with two equivalent Pb(1)O5 trigonal bipyramids and  an edgeedge with one Pb(6)O6 pentagonal pyramid. There are eight inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one O(15), two equivalent O(1), and two equivalent O(6) atoms to form distorted PbO5 trigonal bipyramids that share corners with two equivalent Pb(6)O6 pentagonal pyramids,  a cornercorner with one V(1)O4 tetrahedra, corners with two equivalent V(4)O4 tetrahedra, and  an edgeedge with one Si(1)O4 tetrahedra. In the second Pb site, Pb(2) is bonded to one O(13), two equivalent O(2), and two equivalent O(4) atoms to form distorted PbO5 trigonal bipyramids that share corners with two equivalent Pb(6)O6 pentagonal pyramids,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent V(2)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. In the third Pb site, Pb(3) is bonded to one O(14), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form distorted PbO6 pentagonal pyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent V(3)O4 tetrahedra, and  an edgeedge with one V(1)O4 tetrahedra. In the fourth Pb site, Pb(4) is bonded in a 6-coordinate geometry to one O(11), one O(18), two equivalent O(3), and two equivalent O(4) atoms. In the fifth Pb site, Pb(5) is bonded in a 6-coordinate geometry to one O(12), one O(16), two equivalent O(1), and two equivalent O(5) atoms. In the sixth Pb site, Pb(6) is bonded to one O(10), one O(17), two equivalent O(2), and two equivalent O(6) atoms to form distorted PbO6 pentagonal pyramids that share  a cornercorner with one V(2)O4 tetrahedra,  a cornercorner with one V(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Pb(1)O5 trigonal bipyramids, corners with two equivalent Pb(2)O5 trigonal bipyramids, and  an edgeedge with one V(4)O4 tetrahedra. In the seventh Pb site, Pb(7) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(12), one O(13), one O(14), and one O(15) atom. In the eighth Pb site, Pb(8) is bonded in a 3-coordinate geometry to one O(7), one O(8), and one O(9) atom. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(13), one O(7), and two equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Pb(3)O6 pentagonal pyramid,  a cornercorner with one Pb(2)O5 trigonal bipyramid, and  an edgeedge with one Pb(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(14), one O(8), and two equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Pb(3)O6 pentagonal pyramid, corners with two equivalent Pb(6)O6 pentagonal pyramids, and  an edgeedge with one Pb(2)O5 trigonal bipyramid. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Pb(1), one Pb(5), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Pb(2), one Pb(6), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one V(1), one Pb(3), and one Pb(4) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one V(2), one Pb(2), and one Pb(4) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one V(3), one Pb(3), and one Pb(5) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one V(4), one Pb(1), and one Pb(6) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Pb(3), two equivalent Pb(8), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Pb(8) and one Si(2) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one V(1) and two equivalent Pb(8) atoms. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one V(2), one Pb(6), and two equivalent Pb(7) atoms. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one V(3), one Pb(4), and two equivalent Pb(7) atoms. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one V(4), one Pb(5), and two equivalent Pb(7) atoms. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Pb(2), two equivalent Pb(7), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a 2-coordinate geometry to one Pb(3), two equivalent Pb(7), and one Si(2) atom. In the fifteenth O site, O(15) is bonded in a 2-coordinate geometry to one V(1), one Pb(1), and two equivalent Pb(7) atoms. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to one V(2) and one Pb(5) atom. In the seventeenth O site, O(17) is bonded in a 2-coordinate geometry to one V(3) and one Pb(6) atom. In the eighteenth O site, O(18) is bonded in a distorted bent 120 degrees geometry to one V(4) and one Pb(4) atom.
V2Pb5SiO12 crystallizes in the monoclinic Pm space group. There are four inequivalent V sites. In the first V site, V(1) is bonded to one O(15), one O(9), and two equivalent O(3) atoms to form VO4 tetrahedra that share  a cornercorner with one Pb(1)O5 trigonal bipyramid and  an edgeedge with one Pb(3)O6 pentagonal pyramid. The V(1)-O(15) bond length is 1.77 Å. The V(1)-O(9) bond length is 1.75 Å. Both V(1)-O(3) bond lengths are 1.73 Å. In the second V site, V(2) is bonded to one O(10), one O(16), and two equivalent O(4) atoms to form VO4 tetrahedra that share  a cornercorner with one Pb(6)O6 pentagonal pyramid and corners with two equivalent Pb(2)O5 trigonal bipyramids. The V(2)-O(10) bond length is 1.77 Å. The V(2)-O(16) bond length is 1.76 Å. Both V(2)-O(4) bond lengths are 1.73 Å. In the third V site, V(3) is bonded to one O(11), one O(17), and two equivalent O(5) atoms to form VO4 tetrahedra that share  a cornercorner with one Pb(6)O6 pentagonal pyramid and corners with two equivalent Pb(3)O6 pentagonal pyramids. The V(3)-O(11) bond length is 1.75 Å. The V(3)-O(17) bond length is 1.77 Å. Both V(3)-O(5) bond lengths are 1.73 Å. In the fourth V site, V(4) is bonded to one O(12), one O(18), and two equivalent O(6) atoms to form VO4 tetrahedra that share corners with two equivalent Pb(1)O5 trigonal bipyramids and  an edgeedge with one Pb(6)O6 pentagonal pyramid. The V(4)-O(12) bond length is 1.77 Å. The V(4)-O(18) bond length is 1.77 Å. Both V(4)-O(6) bond lengths are 1.73 Å. There are eight inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one O(15), two equivalent O(1), and two equivalent O(6) atoms to form distorted PbO5 trigonal bipyramids that share corners with two equivalent Pb(6)O6 pentagonal pyramids,  a cornercorner with one V(1)O4 tetrahedra, corners with two equivalent V(4)O4 tetrahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The Pb(1)-O(15) bond length is 2.28 Å. Both Pb(1)-O(1) bond lengths are 2.50 Å. Both Pb(1)-O(6) bond lengths are 2.62 Å. In the second Pb site, Pb(2) is bonded to one O(13), two equivalent O(2), and two equivalent O(4) atoms to form distorted PbO5 trigonal bipyramids that share corners with two equivalent Pb(6)O6 pentagonal pyramids,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent V(2)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. The Pb(2)-O(13) bond length is 2.28 Å. Both Pb(2)-O(2) bond lengths are 2.49 Å. Both Pb(2)-O(4) bond lengths are 2.62 Å. In the third Pb site, Pb(3) is bonded to one O(14), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form distorted PbO6 pentagonal pyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent V(3)O4 tetrahedra, and  an edgeedge with one V(1)O4 tetrahedra. The Pb(3)-O(14) bond length is 2.26 Å. The Pb(3)-O(7) bond length is 2.77 Å. Both Pb(3)-O(3) bond lengths are 2.73 Å. Both Pb(3)-O(5) bond lengths are 2.50 Å. In the fourth Pb site, Pb(4) is bonded in a 6-coordinate geometry to one O(11), one O(18), two equivalent O(3), and two equivalent O(4) atoms. The Pb(4)-O(11) bond length is 2.84 Å. The Pb(4)-O(18) bond length is 2.24 Å. Both Pb(4)-O(3) bond lengths are 2.53 Å. Both Pb(4)-O(4) bond lengths are 2.67 Å. In the fifth Pb site, Pb(5) is bonded in a 6-coordinate geometry to one O(12), one O(16), two equivalent O(1), and two equivalent O(5) atoms. The Pb(5)-O(12) bond length is 2.66 Å. The Pb(5)-O(16) bond length is 2.27 Å. Both Pb(5)-O(1) bond lengths are 2.55 Å. Both Pb(5)-O(5) bond lengths are 2.79 Å. In the sixth Pb site, Pb(6) is bonded to one O(10), one O(17), two equivalent O(2), and two equivalent O(6) atoms to form distorted PbO6 pentagonal pyramids that share  a cornercorner with one V(2)O4 tetrahedra,  a cornercorner with one V(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Pb(1)O5 trigonal bipyramids, corners with two equivalent Pb(2)O5 trigonal bipyramids, and  an edgeedge with one V(4)O4 tetrahedra. The Pb(6)-O(10) bond length is 2.75 Å. The Pb(6)-O(17) bond length is 2.26 Å. Both Pb(6)-O(2) bond lengths are 2.59 Å. Both Pb(6)-O(6) bond lengths are 2.71 Å. In the seventh Pb site, Pb(7) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(12), one O(13), one O(14), and one O(15) atom. The Pb(7)-O(10) bond length is 2.51 Å. The Pb(7)-O(11) bond length is 2.60 Å. The Pb(7)-O(12) bond length is 2.59 Å. The Pb(7)-O(13) bond length is 2.72 Å. The Pb(7)-O(14) bond length is 2.80 Å. The Pb(7)-O(15) bond length is 2.83 Å. In the eighth Pb site, Pb(8) is bonded in a 3-coordinate geometry to one O(7), one O(8), and one O(9) atom. The Pb(8)-O(7) bond length is 2.48 Å. The Pb(8)-O(8) bond length is 2.42 Å. The Pb(8)-O(9) bond length is 2.48 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(13), one O(7), and two equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Pb(3)O6 pentagonal pyramid,  a cornercorner with one Pb(2)O5 trigonal bipyramid, and  an edgeedge with one Pb(1)O5 trigonal bipyramid. The Si(1)-O(13) bond length is 1.67 Å. The Si(1)-O(7) bond length is 1.66 Å. Both Si(1)-O(1) bond lengths are 1.66 Å. In the second Si site, Si(2) is bonded to one O(14), one O(8), and two equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Pb(3)O6 pentagonal pyramid, corners with two equivalent Pb(6)O6 pentagonal pyramids, and  an edgeedge with one Pb(2)O5 trigonal bipyramid. The Si(2)-O(14) bond length is 1.67 Å. The Si(2)-O(8) bond length is 1.65 Å. Both Si(2)-O(2) bond lengths are 1.66 Å. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Pb(1), one Pb(5), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Pb(2), one Pb(6), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one V(1), one Pb(3), and one Pb(4) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one V(2), one Pb(2), and one Pb(4) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one V(3), one Pb(3), and one Pb(5) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one V(4), one Pb(1), and one Pb(6) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Pb(3), two equivalent Pb(8), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Pb(8) and one Si(2) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one V(1) and two equivalent Pb(8) atoms. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one V(2), one Pb(6), and two equivalent Pb(7) atoms. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one V(3), one Pb(4), and two equivalent Pb(7) atoms. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one V(4), one Pb(5), and two equivalent Pb(7) atoms. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Pb(2), two equivalent Pb(7), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a 2-coordinate geometry to one Pb(3), two equivalent Pb(7), and one Si(2) atom. In the fifteenth O site, O(15) is bonded in a 2-coordinate geometry to one V(1), one Pb(1), and two equivalent Pb(7) atoms. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to one V(2) and one Pb(5) atom. In the seventeenth O site, O(17) is bonded in a 2-coordinate geometry to one V(3) and one Pb(6) atom. In the eighteenth O site, O(18) is bonded in a distorted bent 120 degrees geometry to one V(4) and one Pb(4) atom.