The material structure described by Gd7Y5Nb4O28 crystallizes in the triclinic P1 space group. There are seven inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(12), one O(16), one O(18), one O(2), one O(24), one O(28), and one O(6) atom to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Gd(3)O7 pentagonal bipyramid,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Gd(2)O7 pentagonal bipyramid, and edges with two equivalent Y(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 40-51°. In the second Gd site, Gd(2) is bonded to one O(11), one O(16), one O(18), one O(22), one O(25), one O(4), and one O(7) atom to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Y(5)O7 pentagonal bipyramid,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Gd(1)O7 pentagonal bipyramid, and edges with two equivalent Y(4)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 41-51°. In the third Gd site, Gd(3) is bonded to one O(12), one O(15), one O(17), one O(21), one O(26), one O(3), and one O(8) atom to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Y(5)O7 pentagonal bipyramid, and edges with two equivalent Y(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 40-51°. In the fourth Gd site, Gd(4) is bonded in a 6-coordinate geometry to one O(11), one O(17), one O(19), one O(21), one O(27), and one O(9) atom. In the fifth Gd site, Gd(5) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(18), one O(20), one O(22), and one O(28) atom. In the sixth Gd site, Gd(6) is bonded in a 8-coordinate geometry to one O(11), one O(17), one O(19), one O(23), one O(25), one O(3), one O(5), and one O(9) atom. In the seventh Gd site, Gd(7) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(18), one O(20), one O(24), one O(26), one O(4), and one O(6) atom. There are five inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(1), one O(13), one O(19), one O(23), one O(27), one O(5), and one O(9) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Y(4)O7 pentagonal bipyramid, and edges with two equivalent Y(5)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 39-50°. In the second Y site, Y(2) is bonded to one O(10), one O(14), one O(2), one O(20), one O(24), one O(28), and one O(6) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Y(4)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Y(3)O7 pentagonal bipyramid, and edges with two equivalent Gd(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-49°. In the third Y site, Y(3) is bonded to one O(14), one O(20), one O(21), one O(26), one O(3), one O(8), and one O(9) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Y(2)O7 pentagonal bipyramid, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-49°. In the fourth Y site, Y(4) is bonded to one O(10), one O(13), one O(19), one O(22), one O(25), one O(4), and one O(7) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Y(2)O7 pentagonal bipyramid,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Y(1)O7 pentagonal bipyramid, and edges with two equivalent Gd(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-49°. In the fifth Y site, Y(5) is bonded to one O(1), one O(11), one O(15), one O(17), one O(23), one O(27), and one O(5) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Gd(2)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Gd(3)O7 pentagonal bipyramid, and edges with two equivalent Y(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 39-50°. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(14), one O(15), one O(2), one O(21), one O(27), and one O(8) atom to form NbO6 octahedra that share corners with two equivalent Nb(4)O6 octahedra,  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  a cornercorner with one Gd(3)O7 pentagonal bipyramid,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  an edgeedge with one Gd(3)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O7 pentagonal bipyramid,  an edgeedge with one Y(3)O7 pentagonal bipyramid, and  an edgeedge with one Y(5)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-43°. In the second Nb site, Nb(2) is bonded to one O(1), one O(13), one O(16), one O(22), one O(28), and one O(7) atom to form NbO6 octahedra that share corners with two equivalent Nb(3)O6 octahedra,  a cornercorner with one Gd(2)O7 pentagonal bipyramid,  a cornercorner with one Y(2)O7 pentagonal bipyramid,  a cornercorner with one Y(4)O7 pentagonal bipyramid,  a cornercorner with one Y(5)O7 pentagonal bipyramid,  an edgeedge with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Gd(2)O7 pentagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid, and  an edgeedge with one Y(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-44°. In the third Nb site, Nb(3) is bonded to one O(13), one O(16), one O(23), one O(25), one O(4), and one O(6) atom to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra,  a cornercorner with one Gd(2)O7 pentagonal bipyramid,  a cornercorner with one Y(2)O7 pentagonal bipyramid,  a cornercorner with one Y(4)O7 pentagonal bipyramid,  a cornercorner with one Y(5)O7 pentagonal bipyramid,  an edgeedge with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Gd(2)O7 pentagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid, and  an edgeedge with one Y(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-44°. In the fourth Nb site, Nb(4) is bonded to one O(14), one O(15), one O(24), one O(26), one O(3), and one O(5) atom to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra,  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  a cornercorner with one Gd(3)O7 pentagonal bipyramid,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  an edgeedge with one Gd(3)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O7 pentagonal bipyramid,  an edgeedge with one Y(3)O7 pentagonal bipyramid, and  an edgeedge with one Y(5)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-43°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Y(1), one Y(5), and one Nb(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Gd(1), one Y(2), and one Nb(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Gd(3), one Gd(6), one Y(3), and one Nb(4) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Gd(2), one Gd(7), one Y(4), and one Nb(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Gd(6), one Y(1), one Y(5), and one Nb(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Gd(1), one Gd(7), one Y(2), and one Nb(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Gd(2), one Y(4), and one Nb(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Gd(3), one Y(3), and one Nb(1) atom. In the ninth O site, O(9) is bonded to one Gd(4), one Gd(6), one Y(1), and one Y(3) atom to form OGd2Y2 tetrahedra that share  a cornercorner with one O(19)Gd2Y2 tetrahedra,  a cornercorner with one O(20)Gd2Y2 tetrahedra,  a cornercorner with one O(25)Gd2YNb tetrahedra,  a cornercorner with one O(26)Gd2YNb tetrahedra, corners with two equivalent O(11)Gd3Y tetrahedra, corners with two equivalent O(17)Gd3Y tetrahedra, corners with two equivalent O(27)GdY2Nb tetrahedra,  a cornercorner with one O(13)Y2Nb2 trigonal pyramid,  a cornercorner with one O(14)Y2Nb2 trigonal pyramid,  an edgeedge with one O(19)Gd2Y2 tetrahedra,  an edgeedge with one O(21)Gd2YNb tetrahedra, and  an edgeedge with one O(23)GdY2Nb tetrahedra. In the tenth O site, O(10) is bonded to one Gd(5), one Gd(7), one Y(2), and one Y(4) atom to form OGd2Y2 tetrahedra that share  a cornercorner with one O(19)Gd2Y2 tetrahedra,  a cornercorner with one O(20)Gd2Y2 tetrahedra,  a cornercorner with one O(25)Gd2YNb tetrahedra,  a cornercorner with one O(26)Gd2YNb tetrahedra, corners with two equivalent O(28)Gd2YNb tetrahedra, corners with two equivalent O(12)Gd4 tetrahedra, corners with two equivalent O(18)Gd4 tetrahedra,  a cornercorner with one O(13)Y2Nb2 trigonal pyramid,  a cornercorner with one O(14)Y2Nb2 trigonal pyramid,  an edgeedge with one O(20)Gd2Y2 tetrahedra,  an edgeedge with one O(22)Gd2YNb tetrahedra, and  an edgeedge with one O(24)Gd2YNb tetrahedra. In the eleventh O site, O(11) is bonded to one Gd(2), one Gd(4), one Gd(6), and one Y(5) atom to form OGd3Y tetrahedra that share  a cornercorner with one O(21)Gd2YNb tetrahedra,  a cornercorner with one O(22)Gd2YNb tetrahedra,  a cornercorner with one O(17)Gd3Y tetrahedra,  a cornercorner with one O(18)Gd4 tetrahedra, corners with two equivalent O(19)Gd2Y2 tetrahedra, corners with two equivalent O(9)Gd2Y2 tetrahedra, corners with two equivalent O(23)GdY2Nb tetrahedra,  a cornercorner with one O(16)Gd2Nb2 trigonal pyramid,  a cornercorner with one O(15)GdYNb2 trigonal pyramid,  an edgeedge with one O(25)Gd2YNb tetrahedra,  an edgeedge with one O(17)Gd3Y tetrahedra, and  an edgeedge with one O(27)GdY2Nb tetrahedra. In the twelfth O site, O(12) is bonded to one Gd(1), one Gd(3), one Gd(5), and one Gd(7) atom to form OGd4 tetrahedra that share  a cornercorner with one O(21)Gd2YNb tetrahedra,  a cornercorner with one O(22)Gd2YNb tetrahedra,  a cornercorner with one O(17)Gd3Y tetrahedra,  a cornercorner with one O(18)Gd4 tetrahedra, corners with two equivalent O(10)Gd2Y2 tetrahedra, corners with two equivalent O(20)Gd2Y2 tetrahedra, corners with two equivalent O(24)Gd2YNb tetrahedra,  a cornercorner with one O(16)Gd2Nb2 trigonal pyramid,  a cornercorner with one O(15)GdYNb2 trigonal pyramid,  an edgeedge with one O(26)Gd2YNb tetrahedra,  an edgeedge with one O(28)Gd2YNb tetrahedra, and  an edgeedge with one O(18)Gd4 tetrahedra. In the thirteenth O site, O(13) is bonded to one Y(1), one Y(4), one Nb(2), and one Nb(3) atom to form distorted OY2Nb2 trigonal pyramids that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(28)Gd2YNb tetrahedra,  a cornercorner with one O(27)GdY2Nb tetrahedra, corners with two equivalent O(25)Gd2YNb tetrahedra, corners with two equivalent O(16)Gd2Nb2 trigonal pyramids,  an edgeedge with one O(19)Gd2Y2 tetrahedra,  an edgeedge with one O(22)Gd2YNb tetrahedra, and  an edgeedge with one O(23)GdY2Nb tetrahedra. In the fourteenth O site, O(14) is bonded to one Y(2), one Y(3), one Nb(1), and one Nb(4) atom to form distorted OY2Nb2 trigonal pyramids that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(28)Gd2YNb tetrahedra,  a cornercorner with one O(27)GdY2Nb tetrahedra, corners with two equivalent O(26)Gd2YNb tetrahedra, corners with two equivalent O(15)GdYNb2 trigonal pyramids,  an edgeedge with one O(20)Gd2Y2 tetrahedra,  an edgeedge with one O(21)Gd2YNb tetrahedra, and  an edgeedge with one O(24)Gd2YNb tetrahedra. In the fifteenth O site, O(15) is bonded to one Gd(3), one Y(5), one Nb(1), and one Nb(4) atom to form distorted OGdYNb2 trigonal pyramids that share  a cornercorner with one O(24)Gd2YNb tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra,  a cornercorner with one O(23)GdY2Nb tetrahedra, corners with two equivalent O(21)Gd2YNb tetrahedra, corners with two equivalent O(14)Y2Nb2 trigonal pyramids,  an edgeedge with one O(26)Gd2YNb tetrahedra,  an edgeedge with one O(17)Gd3Y tetrahedra, and  an edgeedge with one O(27)GdY2Nb tetrahedra. In the sixteenth O site, O(16) is bonded to one Gd(1), one Gd(2), one Nb(2), and one Nb(3) atom to form distorted OGd2Nb2 trigonal pyramids that share  a cornercorner with one O(24)Gd2YNb tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra,  a cornercorner with one O(23)GdY2Nb tetrahedra, corners with two equivalent O(22)Gd2YNb tetrahedra, corners with two equivalent O(13)Y2Nb2 trigonal pyramids,  an edgeedge with one O(25)Gd2YNb tetrahedra,  an edgeedge with one O(28)Gd2YNb tetrahedra, and  an edgeedge with one O(18)Gd4 tetrahedra. In the seventeenth O site, O(17) is bonded to one Gd(3), one Gd(4), one Gd(6), and one Y(5) atom to form OGd3Y tetrahedra that share  a cornercorner with one O(25)Gd2YNb tetrahedra,  a cornercorner with one O(26)Gd2YNb tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra, corners with two equivalent O(19)Gd2Y2 tetrahedra, corners with two equivalent O(9)Gd2Y2 tetrahedra, corners with two equivalent O(27)GdY2Nb tetrahedra,  an edgeedge with one O(21)Gd2YNb tetrahedra,  an edgeedge with one O(11)Gd3Y tetrahedra,  an edgeedge with one O(23)GdY2Nb tetrahedra, and  an edgeedge with one O(15)GdYNb2 trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Gd(1), one Gd(2), one Gd(5), and one Gd(7) atom to form OGd4 tetrahedra that share  a cornercorner with one O(25)Gd2YNb tetrahedra,  a cornercorner with one O(26)Gd2YNb tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra, corners with two equivalent O(10)Gd2Y2 tetrahedra, corners with two equivalent O(20)Gd2Y2 tetrahedra, corners with two equivalent O(28)Gd2YNb tetrahedra,  an edgeedge with one O(22)Gd2YNb tetrahedra,  an edgeedge with one O(24)Gd2YNb tetrahedra,  an edgeedge with one O(12)Gd4 tetrahedra, and  an edgeedge with one O(16)Gd2Nb2 trigonal pyramid. In the nineteenth O site, O(19) is bonded to one Gd(4), one Gd(6), one Y(1), and one Y(4) atom to form OGd2Y2 tetrahedra that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(21)Gd2YNb tetrahedra,  a cornercorner with one O(22)Gd2YNb tetrahedra, corners with two equivalent O(11)Gd3Y tetrahedra, corners with two equivalent O(17)Gd3Y tetrahedra, corners with two equivalent O(23)GdY2Nb tetrahedra,  an edgeedge with one O(9)Gd2Y2 tetrahedra,  an edgeedge with one O(25)Gd2YNb tetrahedra,  an edgeedge with one O(27)GdY2Nb tetrahedra, and  an edgeedge with one O(13)Y2Nb2 trigonal pyramid. In the twentieth O site, O(20) is bonded to one Gd(5), one Gd(7), one Y(2), and one Y(3) atom to form OGd2Y2 tetrahedra that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(21)Gd2YNb tetrahedra,  a cornercorner with one O(22)Gd2YNb tetrahedra, corners with two equivalent O(24)Gd2YNb tetrahedra, corners with two equivalent O(12)Gd4 tetrahedra, corners with two equivalent O(18)Gd4 tetrahedra,  an edgeedge with one O(10)Gd2Y2 tetrahedra,  an edgeedge with one O(26)Gd2YNb tetrahedra,  an edgeedge with one O(28)Gd2YNb tetrahedra, and  an edgeedge with one O(14)Y2Nb2 trigonal pyramid. In the twenty-first O site, O(21) is bonded to one Gd(3), one Gd(4), one Y(3), and one Nb(1) atom to form OGd2YNb tetrahedra that share  a cornercorner with one O(19)Gd2Y2 tetrahedra,  a cornercorner with one O(20)Gd2Y2 tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra, corners with two equivalent O(26)Gd2YNb tetrahedra, corners with two equivalent O(15)GdYNb2 trigonal pyramids,  an edgeedge with one O(9)Gd2Y2 tetrahedra,  an edgeedge with one O(17)Gd3Y tetrahedra,  an edgeedge with one O(27)GdY2Nb tetrahedra, and  an edgeedge with one O(14)Y2Nb2 trigonal pyramid. In the twenty-second O site, O(22) is bonded to one Gd(2), one Gd(5), one Y(4), and one Nb(2) atom to form OGd2YNb tetrahedra that share  a cornercorner with one O(19)Gd2Y2 tetrahedra,  a cornercorner with one O(20)Gd2Y2 tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra, corners with two equivalent O(25)Gd2YNb tetrahedra, corners with two equivalent O(16)Gd2Nb2 trigonal pyramids,  an edgeedge with one O(10)Gd2Y2 tetrahedra,  an edgeedge with one O(28)Gd2YNb tetrahedra,  an edgeedge with one O(18)Gd4 tetrahedra, and  an edgeedge with one O(13)Y2Nb2 trigonal pyramid. In the twenty-third O site, O(23) is bonded to one Gd(6), one Y(1), one Y(5), and one Nb(3) atom to form OGdY2Nb tetrahedra that share corners with two equivalent O(19)Gd2Y2 tetrahedra, corners with two equivalent O(11)Gd3Y tetrahedra, corners with two equivalent O(27)GdY2Nb tetrahedra,  a cornercorner with one O(16)Gd2Nb2 trigonal pyramid,  a cornercorner with one O(15)GdYNb2 trigonal pyramid,  an edgeedge with one O(9)Gd2Y2 tetrahedra,  an edgeedge with one O(25)Gd2YNb tetrahedra,  an edgeedge with one O(17)Gd3Y tetrahedra, and  an edgeedge with one O(13)Y2Nb2 trigonal pyramid. In the twenty-fourth O site, O(24) is bonded to one Gd(1), one Gd(7), one Y(2), and one Nb(4) atom to form OGd2YNb tetrahedra that share corners with two equivalent O(20)Gd2Y2 tetrahedra, corners with two equivalent O(28)Gd2YNb tetrahedra, corners with two equivalent O(12)Gd4 tetrahedra,  a cornercorner with one O(16)Gd2Nb2 trigonal pyramid,  a cornercorner with one O(15)GdYNb2 trigonal pyramid,  an edgeedge with one O(10)Gd2Y2 tetrahedra,  an edgeedge with one O(26)Gd2YNb tetrahedra,  an edgeedge with one O(18)Gd4 tetrahedra, and  an edgeedge with one O(14)Y2Nb2 trigonal pyramid. In the twenty-fifth O site, O(25) is bonded to one Gd(2), one Gd(6), one Y(4), and one Nb(3) atom to form distorted OGd2YNb tetrahedra that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(17)Gd3Y tetrahedra,  a cornercorner with one O(18)Gd4 tetrahedra, corners with two equivalent O(22)Gd2YNb tetrahedra, corners with two equivalent O(13)Y2Nb2 trigonal pyramids,  an edgeedge with one O(19)Gd2Y2 tetrahedra,  an edgeedge with one O(11)Gd3Y tetrahedra,  an edgeedge with one O(23)GdY2Nb tetrahedra, and  an edgeedge with one O(16)Gd2Nb2 trigonal pyramid. In the twenty-sixth O site, O(26) is bonded to one Gd(3), one Gd(7), one Y(3), and one Nb(4) atom to form distorted OGd2YNb tetrahedra that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(17)Gd3Y tetrahedra,  a cornercorner with one O(18)Gd4 tetrahedra, corners with two equivalent O(21)Gd2YNb tetrahedra, corners with two equivalent O(14)Y2Nb2 trigonal pyramids,  an edgeedge with one O(20)Gd2Y2 tetrahedra,  an edgeedge with one O(24)Gd2YNb tetrahedra,  an edgeedge with one O(12)Gd4 tetrahedra, and  an edgeedge with one O(15)GdYNb2 trigonal pyramid. In the twenty-seventh O site, O(27) is bonded to one Gd(4), one Y(1), one Y(5), and one Nb(1) atom to form OGdY2Nb tetrahedra that share corners with two equivalent O(9)Gd2Y2 tetrahedra, corners with two equivalent O(17)Gd3Y tetrahedra, corners with two equivalent O(23)GdY2Nb tetrahedra,  a cornercorner with one O(13)Y2Nb2 trigonal pyramid,  a cornercorner with one O(14)Y2Nb2 trigonal pyramid,  an edgeedge with one O(19)Gd2Y2 tetrahedra,  an edgeedge with one O(21)Gd2YNb tetrahedra,  an edgeedge with one O(11)Gd3Y tetrahedra, and  an edgeedge with one O(15)GdYNb2 trigonal pyramid. In the twenty-eighth O site, O(28) is bonded to one Gd(1), one Gd(5), one Y(2), and one Nb(2) atom to form distorted OGd2YNb tetrahedra that share corners with two equivalent O(10)Gd2Y2 tetrahedra, corners with two equivalent O(24)Gd2YNb tetrahedra, corners with two equivalent O(18)Gd4 tetrahedra,  a cornercorner with one O(13)Y2Nb2 trigonal pyramid,  a cornercorner with one O(14)Y2Nb2 trigonal pyramid,  an edgeedge with one O(20)Gd2Y2 tetrahedra,  an edgeedge with one O(22)Gd2YNb tetrahedra,  an edgeedge with one O(12)Gd4 tetrahedra, and  an edgeedge with one O(16)Gd2Nb2 trigonal pyramid. is represented by the CIF file [CIF]
data_Gd7Y5Nb4O28
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.543
_cell_length_b   7.566
_cell_length_c   12.597
_cell_angle_alpha   89.926
_cell_angle_beta   79.309
_cell_angle_gamma   89.955
_symmetry_Int_Tables_number   1
_cell_volume   612.721
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Gd  Gd0  1  0.232  0.008  0.768  1.0
  Gd  Gd1  1  0.465  0.993  0.001  1.0
  Gd  Gd2  1  0.964  0.992  0.500  1.0
  Gd  Gd3  1  0.268  0.749  0.267  1.0
  Gd  Gd4  1  0.767  0.748  0.767  1.0
  Gd  Gd5  1  0.233  0.251  0.234  1.0
  Gd  Gd6  1  0.732  0.251  0.733  1.0
  Y  Y7  1  0.769  0.508  0.232  1.0
  Y  Y8  1  0.269  0.508  0.732  1.0
  Y  Y9  1  0.038  0.492  0.499  1.0
  Y  Y10  1  0.537  0.492  0.000  1.0
  Y  Y11  1  0.732  0.007  0.268  1.0
  Nb  Nb12  1  0.503  0.749  0.501  1.0
  Nb  Nb13  1  0.002  0.749  0.002  1.0
  Nb  Nb14  1  0.999  0.251  0.999  1.0
  Nb  Nb15  1  0.500  0.251  0.498  1.0
  O  O16  1  0.897  0.794  0.154  1.0
  O  O17  1  0.399  0.791  0.654  1.0
  O  O18  1  0.218  0.209  0.472  1.0
  O  O19  1  0.718  0.210  0.973  1.0
  O  O20  1  0.603  0.294  0.346  1.0
  O  O21  1  0.102  0.297  0.847  1.0
  O  O22  1  0.281  0.703  0.026  1.0
  O  O23  1  0.781  0.703  0.525  1.0
  O  O24  1  0.054  0.500  0.315  1.0
  O  O25  1  0.553  0.500  0.815  1.0
  O  O26  1  0.447  0.001  0.187  1.0
  O  O27  1  0.944  1.000  0.685  1.0
  O  O28  1  0.895  0.500  0.037  1.0
  O  O29  1  0.396  0.500  0.534  1.0
  O  O30  1  0.600  1.000  0.466  1.0
  O  O31  1  0.099  0.000  0.967  1.0
  O  O32  1  0.040  0.999  0.319  1.0
  O  O33  1  0.542  0.000  0.820  1.0
  O  O34  1  0.462  0.500  0.180  1.0
  O  O35  1  0.962  0.500  0.679  1.0
  O  O36  1  0.212  0.770  0.458  1.0
  O  O37  1  0.711  0.770  0.959  1.0
  O  O38  1  0.916  0.227  0.165  1.0
  O  O39  1  0.418  0.229  0.665  1.0
  O  O40  1  0.287  0.276  0.041  1.0
  O  O41  1  0.787  0.276  0.540  1.0
  O  O42  1  0.585  0.726  0.335  1.0
  O  O43  1  0.083  0.724  0.836  1.0
[/CIF]
.
The material structure described by Gd7Y5Nb4O28 crystallizes in the triclinic P1 space group. There are seven inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(12), one O(16), one O(18), one O(2), one O(24), one O(28), and one O(6) atom to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Gd(3)O7 pentagonal bipyramid,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Gd(2)O7 pentagonal bipyramid, and edges with two equivalent Y(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 40-51°. In the second Gd site, Gd(2) is bonded to one O(11), one O(16), one O(18), one O(22), one O(25), one O(4), and one O(7) atom to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Y(5)O7 pentagonal bipyramid,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Gd(1)O7 pentagonal bipyramid, and edges with two equivalent Y(4)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 41-51°. In the third Gd site, Gd(3) is bonded to one O(12), one O(15), one O(17), one O(21), one O(26), one O(3), and one O(8) atom to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Y(5)O7 pentagonal bipyramid, and edges with two equivalent Y(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 40-51°. In the fourth Gd site, Gd(4) is bonded in a 6-coordinate geometry to one O(11), one O(17), one O(19), one O(21), one O(27), and one O(9) atom. In the fifth Gd site, Gd(5) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(18), one O(20), one O(22), and one O(28) atom. In the sixth Gd site, Gd(6) is bonded in a 8-coordinate geometry to one O(11), one O(17), one O(19), one O(23), one O(25), one O(3), one O(5), and one O(9) atom. In the seventh Gd site, Gd(7) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(18), one O(20), one O(24), one O(26), one O(4), and one O(6) atom. There are five inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(1), one O(13), one O(19), one O(23), one O(27), one O(5), and one O(9) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Y(4)O7 pentagonal bipyramid, and edges with two equivalent Y(5)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 39-50°. In the second Y site, Y(2) is bonded to one O(10), one O(14), one O(2), one O(20), one O(24), one O(28), and one O(6) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Y(4)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Y(3)O7 pentagonal bipyramid, and edges with two equivalent Gd(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-49°. In the third Y site, Y(3) is bonded to one O(14), one O(20), one O(21), one O(26), one O(3), one O(8), and one O(9) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Y(2)O7 pentagonal bipyramid, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-49°. In the fourth Y site, Y(4) is bonded to one O(10), one O(13), one O(19), one O(22), one O(25), one O(4), and one O(7) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Y(2)O7 pentagonal bipyramid,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Y(1)O7 pentagonal bipyramid, and edges with two equivalent Gd(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-49°. In the fifth Y site, Y(5) is bonded to one O(1), one O(11), one O(15), one O(17), one O(23), one O(27), and one O(5) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Gd(2)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Gd(3)O7 pentagonal bipyramid, and edges with two equivalent Y(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 39-50°. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(14), one O(15), one O(2), one O(21), one O(27), and one O(8) atom to form NbO6 octahedra that share corners with two equivalent Nb(4)O6 octahedra,  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  a cornercorner with one Gd(3)O7 pentagonal bipyramid,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  an edgeedge with one Gd(3)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O7 pentagonal bipyramid,  an edgeedge with one Y(3)O7 pentagonal bipyramid, and  an edgeedge with one Y(5)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-43°. In the second Nb site, Nb(2) is bonded to one O(1), one O(13), one O(16), one O(22), one O(28), and one O(7) atom to form NbO6 octahedra that share corners with two equivalent Nb(3)O6 octahedra,  a cornercorner with one Gd(2)O7 pentagonal bipyramid,  a cornercorner with one Y(2)O7 pentagonal bipyramid,  a cornercorner with one Y(4)O7 pentagonal bipyramid,  a cornercorner with one Y(5)O7 pentagonal bipyramid,  an edgeedge with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Gd(2)O7 pentagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid, and  an edgeedge with one Y(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-44°. In the third Nb site, Nb(3) is bonded to one O(13), one O(16), one O(23), one O(25), one O(4), and one O(6) atom to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra,  a cornercorner with one Gd(2)O7 pentagonal bipyramid,  a cornercorner with one Y(2)O7 pentagonal bipyramid,  a cornercorner with one Y(4)O7 pentagonal bipyramid,  a cornercorner with one Y(5)O7 pentagonal bipyramid,  an edgeedge with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Gd(2)O7 pentagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid, and  an edgeedge with one Y(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-44°. In the fourth Nb site, Nb(4) is bonded to one O(14), one O(15), one O(24), one O(26), one O(3), and one O(5) atom to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra,  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  a cornercorner with one Gd(3)O7 pentagonal bipyramid,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  an edgeedge with one Gd(3)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O7 pentagonal bipyramid,  an edgeedge with one Y(3)O7 pentagonal bipyramid, and  an edgeedge with one Y(5)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-43°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Y(1), one Y(5), and one Nb(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Gd(1), one Y(2), and one Nb(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Gd(3), one Gd(6), one Y(3), and one Nb(4) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Gd(2), one Gd(7), one Y(4), and one Nb(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Gd(6), one Y(1), one Y(5), and one Nb(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Gd(1), one Gd(7), one Y(2), and one Nb(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Gd(2), one Y(4), and one Nb(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Gd(3), one Y(3), and one Nb(1) atom. In the ninth O site, O(9) is bonded to one Gd(4), one Gd(6), one Y(1), and one Y(3) atom to form OGd2Y2 tetrahedra that share  a cornercorner with one O(19)Gd2Y2 tetrahedra,  a cornercorner with one O(20)Gd2Y2 tetrahedra,  a cornercorner with one O(25)Gd2YNb tetrahedra,  a cornercorner with one O(26)Gd2YNb tetrahedra, corners with two equivalent O(11)Gd3Y tetrahedra, corners with two equivalent O(17)Gd3Y tetrahedra, corners with two equivalent O(27)GdY2Nb tetrahedra,  a cornercorner with one O(13)Y2Nb2 trigonal pyramid,  a cornercorner with one O(14)Y2Nb2 trigonal pyramid,  an edgeedge with one O(19)Gd2Y2 tetrahedra,  an edgeedge with one O(21)Gd2YNb tetrahedra, and  an edgeedge with one O(23)GdY2Nb tetrahedra. In the tenth O site, O(10) is bonded to one Gd(5), one Gd(7), one Y(2), and one Y(4) atom to form OGd2Y2 tetrahedra that share  a cornercorner with one O(19)Gd2Y2 tetrahedra,  a cornercorner with one O(20)Gd2Y2 tetrahedra,  a cornercorner with one O(25)Gd2YNb tetrahedra,  a cornercorner with one O(26)Gd2YNb tetrahedra, corners with two equivalent O(28)Gd2YNb tetrahedra, corners with two equivalent O(12)Gd4 tetrahedra, corners with two equivalent O(18)Gd4 tetrahedra,  a cornercorner with one O(13)Y2Nb2 trigonal pyramid,  a cornercorner with one O(14)Y2Nb2 trigonal pyramid,  an edgeedge with one O(20)Gd2Y2 tetrahedra,  an edgeedge with one O(22)Gd2YNb tetrahedra, and  an edgeedge with one O(24)Gd2YNb tetrahedra. In the eleventh O site, O(11) is bonded to one Gd(2), one Gd(4), one Gd(6), and one Y(5) atom to form OGd3Y tetrahedra that share  a cornercorner with one O(21)Gd2YNb tetrahedra,  a cornercorner with one O(22)Gd2YNb tetrahedra,  a cornercorner with one O(17)Gd3Y tetrahedra,  a cornercorner with one O(18)Gd4 tetrahedra, corners with two equivalent O(19)Gd2Y2 tetrahedra, corners with two equivalent O(9)Gd2Y2 tetrahedra, corners with two equivalent O(23)GdY2Nb tetrahedra,  a cornercorner with one O(16)Gd2Nb2 trigonal pyramid,  a cornercorner with one O(15)GdYNb2 trigonal pyramid,  an edgeedge with one O(25)Gd2YNb tetrahedra,  an edgeedge with one O(17)Gd3Y tetrahedra, and  an edgeedge with one O(27)GdY2Nb tetrahedra. In the twelfth O site, O(12) is bonded to one Gd(1), one Gd(3), one Gd(5), and one Gd(7) atom to form OGd4 tetrahedra that share  a cornercorner with one O(21)Gd2YNb tetrahedra,  a cornercorner with one O(22)Gd2YNb tetrahedra,  a cornercorner with one O(17)Gd3Y tetrahedra,  a cornercorner with one O(18)Gd4 tetrahedra, corners with two equivalent O(10)Gd2Y2 tetrahedra, corners with two equivalent O(20)Gd2Y2 tetrahedra, corners with two equivalent O(24)Gd2YNb tetrahedra,  a cornercorner with one O(16)Gd2Nb2 trigonal pyramid,  a cornercorner with one O(15)GdYNb2 trigonal pyramid,  an edgeedge with one O(26)Gd2YNb tetrahedra,  an edgeedge with one O(28)Gd2YNb tetrahedra, and  an edgeedge with one O(18)Gd4 tetrahedra. In the thirteenth O site, O(13) is bonded to one Y(1), one Y(4), one Nb(2), and one Nb(3) atom to form distorted OY2Nb2 trigonal pyramids that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(28)Gd2YNb tetrahedra,  a cornercorner with one O(27)GdY2Nb tetrahedra, corners with two equivalent O(25)Gd2YNb tetrahedra, corners with two equivalent O(16)Gd2Nb2 trigonal pyramids,  an edgeedge with one O(19)Gd2Y2 tetrahedra,  an edgeedge with one O(22)Gd2YNb tetrahedra, and  an edgeedge with one O(23)GdY2Nb tetrahedra. In the fourteenth O site, O(14) is bonded to one Y(2), one Y(3), one Nb(1), and one Nb(4) atom to form distorted OY2Nb2 trigonal pyramids that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(28)Gd2YNb tetrahedra,  a cornercorner with one O(27)GdY2Nb tetrahedra, corners with two equivalent O(26)Gd2YNb tetrahedra, corners with two equivalent O(15)GdYNb2 trigonal pyramids,  an edgeedge with one O(20)Gd2Y2 tetrahedra,  an edgeedge with one O(21)Gd2YNb tetrahedra, and  an edgeedge with one O(24)Gd2YNb tetrahedra. In the fifteenth O site, O(15) is bonded to one Gd(3), one Y(5), one Nb(1), and one Nb(4) atom to form distorted OGdYNb2 trigonal pyramids that share  a cornercorner with one O(24)Gd2YNb tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra,  a cornercorner with one O(23)GdY2Nb tetrahedra, corners with two equivalent O(21)Gd2YNb tetrahedra, corners with two equivalent O(14)Y2Nb2 trigonal pyramids,  an edgeedge with one O(26)Gd2YNb tetrahedra,  an edgeedge with one O(17)Gd3Y tetrahedra, and  an edgeedge with one O(27)GdY2Nb tetrahedra. In the sixteenth O site, O(16) is bonded to one Gd(1), one Gd(2), one Nb(2), and one Nb(3) atom to form distorted OGd2Nb2 trigonal pyramids that share  a cornercorner with one O(24)Gd2YNb tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra,  a cornercorner with one O(23)GdY2Nb tetrahedra, corners with two equivalent O(22)Gd2YNb tetrahedra, corners with two equivalent O(13)Y2Nb2 trigonal pyramids,  an edgeedge with one O(25)Gd2YNb tetrahedra,  an edgeedge with one O(28)Gd2YNb tetrahedra, and  an edgeedge with one O(18)Gd4 tetrahedra. In the seventeenth O site, O(17) is bonded to one Gd(3), one Gd(4), one Gd(6), and one Y(5) atom to form OGd3Y tetrahedra that share  a cornercorner with one O(25)Gd2YNb tetrahedra,  a cornercorner with one O(26)Gd2YNb tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra, corners with two equivalent O(19)Gd2Y2 tetrahedra, corners with two equivalent O(9)Gd2Y2 tetrahedra, corners with two equivalent O(27)GdY2Nb tetrahedra,  an edgeedge with one O(21)Gd2YNb tetrahedra,  an edgeedge with one O(11)Gd3Y tetrahedra,  an edgeedge with one O(23)GdY2Nb tetrahedra, and  an edgeedge with one O(15)GdYNb2 trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Gd(1), one Gd(2), one Gd(5), and one Gd(7) atom to form OGd4 tetrahedra that share  a cornercorner with one O(25)Gd2YNb tetrahedra,  a cornercorner with one O(26)Gd2YNb tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra, corners with two equivalent O(10)Gd2Y2 tetrahedra, corners with two equivalent O(20)Gd2Y2 tetrahedra, corners with two equivalent O(28)Gd2YNb tetrahedra,  an edgeedge with one O(22)Gd2YNb tetrahedra,  an edgeedge with one O(24)Gd2YNb tetrahedra,  an edgeedge with one O(12)Gd4 tetrahedra, and  an edgeedge with one O(16)Gd2Nb2 trigonal pyramid. In the nineteenth O site, O(19) is bonded to one Gd(4), one Gd(6), one Y(1), and one Y(4) atom to form OGd2Y2 tetrahedra that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(21)Gd2YNb tetrahedra,  a cornercorner with one O(22)Gd2YNb tetrahedra, corners with two equivalent O(11)Gd3Y tetrahedra, corners with two equivalent O(17)Gd3Y tetrahedra, corners with two equivalent O(23)GdY2Nb tetrahedra,  an edgeedge with one O(9)Gd2Y2 tetrahedra,  an edgeedge with one O(25)Gd2YNb tetrahedra,  an edgeedge with one O(27)GdY2Nb tetrahedra, and  an edgeedge with one O(13)Y2Nb2 trigonal pyramid. In the twentieth O site, O(20) is bonded to one Gd(5), one Gd(7), one Y(2), and one Y(3) atom to form OGd2Y2 tetrahedra that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(21)Gd2YNb tetrahedra,  a cornercorner with one O(22)Gd2YNb tetrahedra, corners with two equivalent O(24)Gd2YNb tetrahedra, corners with two equivalent O(12)Gd4 tetrahedra, corners with two equivalent O(18)Gd4 tetrahedra,  an edgeedge with one O(10)Gd2Y2 tetrahedra,  an edgeedge with one O(26)Gd2YNb tetrahedra,  an edgeedge with one O(28)Gd2YNb tetrahedra, and  an edgeedge with one O(14)Y2Nb2 trigonal pyramid. In the twenty-first O site, O(21) is bonded to one Gd(3), one Gd(4), one Y(3), and one Nb(1) atom to form OGd2YNb tetrahedra that share  a cornercorner with one O(19)Gd2Y2 tetrahedra,  a cornercorner with one O(20)Gd2Y2 tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra, corners with two equivalent O(26)Gd2YNb tetrahedra, corners with two equivalent O(15)GdYNb2 trigonal pyramids,  an edgeedge with one O(9)Gd2Y2 tetrahedra,  an edgeedge with one O(17)Gd3Y tetrahedra,  an edgeedge with one O(27)GdY2Nb tetrahedra, and  an edgeedge with one O(14)Y2Nb2 trigonal pyramid. In the twenty-second O site, O(22) is bonded to one Gd(2), one Gd(5), one Y(4), and one Nb(2) atom to form OGd2YNb tetrahedra that share  a cornercorner with one O(19)Gd2Y2 tetrahedra,  a cornercorner with one O(20)Gd2Y2 tetrahedra,  a cornercorner with one O(11)Gd3Y tetrahedra,  a cornercorner with one O(12)Gd4 tetrahedra, corners with two equivalent O(25)Gd2YNb tetrahedra, corners with two equivalent O(16)Gd2Nb2 trigonal pyramids,  an edgeedge with one O(10)Gd2Y2 tetrahedra,  an edgeedge with one O(28)Gd2YNb tetrahedra,  an edgeedge with one O(18)Gd4 tetrahedra, and  an edgeedge with one O(13)Y2Nb2 trigonal pyramid. In the twenty-third O site, O(23) is bonded to one Gd(6), one Y(1), one Y(5), and one Nb(3) atom to form OGdY2Nb tetrahedra that share corners with two equivalent O(19)Gd2Y2 tetrahedra, corners with two equivalent O(11)Gd3Y tetrahedra, corners with two equivalent O(27)GdY2Nb tetrahedra,  a cornercorner with one O(16)Gd2Nb2 trigonal pyramid,  a cornercorner with one O(15)GdYNb2 trigonal pyramid,  an edgeedge with one O(9)Gd2Y2 tetrahedra,  an edgeedge with one O(25)Gd2YNb tetrahedra,  an edgeedge with one O(17)Gd3Y tetrahedra, and  an edgeedge with one O(13)Y2Nb2 trigonal pyramid. In the twenty-fourth O site, O(24) is bonded to one Gd(1), one Gd(7), one Y(2), and one Nb(4) atom to form OGd2YNb tetrahedra that share corners with two equivalent O(20)Gd2Y2 tetrahedra, corners with two equivalent O(28)Gd2YNb tetrahedra, corners with two equivalent O(12)Gd4 tetrahedra,  a cornercorner with one O(16)Gd2Nb2 trigonal pyramid,  a cornercorner with one O(15)GdYNb2 trigonal pyramid,  an edgeedge with one O(10)Gd2Y2 tetrahedra,  an edgeedge with one O(26)Gd2YNb tetrahedra,  an edgeedge with one O(18)Gd4 tetrahedra, and  an edgeedge with one O(14)Y2Nb2 trigonal pyramid. In the twenty-fifth O site, O(25) is bonded to one Gd(2), one Gd(6), one Y(4), and one Nb(3) atom to form distorted OGd2YNb tetrahedra that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(17)Gd3Y tetrahedra,  a cornercorner with one O(18)Gd4 tetrahedra, corners with two equivalent O(22)Gd2YNb tetrahedra, corners with two equivalent O(13)Y2Nb2 trigonal pyramids,  an edgeedge with one O(19)Gd2Y2 tetrahedra,  an edgeedge with one O(11)Gd3Y tetrahedra,  an edgeedge with one O(23)GdY2Nb tetrahedra, and  an edgeedge with one O(16)Gd2Nb2 trigonal pyramid. In the twenty-sixth O site, O(26) is bonded to one Gd(3), one Gd(7), one Y(3), and one Nb(4) atom to form distorted OGd2YNb tetrahedra that share  a cornercorner with one O(10)Gd2Y2 tetrahedra,  a cornercorner with one O(9)Gd2Y2 tetrahedra,  a cornercorner with one O(17)Gd3Y tetrahedra,  a cornercorner with one O(18)Gd4 tetrahedra, corners with two equivalent O(21)Gd2YNb tetrahedra, corners with two equivalent O(14)Y2Nb2 trigonal pyramids,  an edgeedge with one O(20)Gd2Y2 tetrahedra,  an edgeedge with one O(24)Gd2YNb tetrahedra,  an edgeedge with one O(12)Gd4 tetrahedra, and  an edgeedge with one O(15)GdYNb2 trigonal pyramid. In the twenty-seventh O site, O(27) is bonded to one Gd(4), one Y(1), one Y(5), and one Nb(1) atom to form OGdY2Nb tetrahedra that share corners with two equivalent O(9)Gd2Y2 tetrahedra, corners with two equivalent O(17)Gd3Y tetrahedra, corners with two equivalent O(23)GdY2Nb tetrahedra,  a cornercorner with one O(13)Y2Nb2 trigonal pyramid,  a cornercorner with one O(14)Y2Nb2 trigonal pyramid,  an edgeedge with one O(19)Gd2Y2 tetrahedra,  an edgeedge with one O(21)Gd2YNb tetrahedra,  an edgeedge with one O(11)Gd3Y tetrahedra, and  an edgeedge with one O(15)GdYNb2 trigonal pyramid. In the twenty-eighth O site, O(28) is bonded to one Gd(1), one Gd(5), one Y(2), and one Nb(2) atom to form distorted OGd2YNb tetrahedra that share corners with two equivalent O(10)Gd2Y2 tetrahedra, corners with two equivalent O(24)Gd2YNb tetrahedra, corners with two equivalent O(18)Gd4 tetrahedra,  a cornercorner with one O(13)Y2Nb2 trigonal pyramid,  a cornercorner with one O(14)Y2Nb2 trigonal pyramid,  an edgeedge with one O(20)Gd2Y2 tetrahedra,  an edgeedge with one O(22)Gd2YNb tetrahedra,  an edgeedge with one O(12)Gd4 tetrahedra, and  an edgeedge with one O(16)Gd2Nb2 trigonal pyramid. is represented by the CIF file [CIF]
data_Gd7Y5Nb4O28
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.543
_cell_length_b   7.566
_cell_length_c   12.597
_cell_angle_alpha   89.926
_cell_angle_beta   79.309
_cell_angle_gamma   89.955
_symmetry_Int_Tables_number   1
_cell_volume   612.721
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Gd  Gd0  1  0.232  0.008  0.768  1.0
  Gd  Gd1  1  0.465  0.993  0.001  1.0
  Gd  Gd2  1  0.964  0.992  0.500  1.0
  Gd  Gd3  1  0.268  0.749  0.267  1.0
  Gd  Gd4  1  0.767  0.748  0.767  1.0
  Gd  Gd5  1  0.233  0.251  0.234  1.0
  Gd  Gd6  1  0.732  0.251  0.733  1.0
  Y  Y7  1  0.769  0.508  0.232  1.0
  Y  Y8  1  0.269  0.508  0.732  1.0
  Y  Y9  1  0.038  0.492  0.499  1.0
  Y  Y10  1  0.537  0.492  0.000  1.0
  Y  Y11  1  0.732  0.007  0.268  1.0
  Nb  Nb12  1  0.503  0.749  0.501  1.0
  Nb  Nb13  1  0.002  0.749  0.002  1.0
  Nb  Nb14  1  0.999  0.251  0.999  1.0
  Nb  Nb15  1  0.500  0.251  0.498  1.0
  O  O16  1  0.897  0.794  0.154  1.0
  O  O17  1  0.399  0.791  0.654  1.0
  O  O18  1  0.218  0.209  0.472  1.0
  O  O19  1  0.718  0.210  0.973  1.0
  O  O20  1  0.603  0.294  0.346  1.0
  O  O21  1  0.102  0.297  0.847  1.0
  O  O22  1  0.281  0.703  0.026  1.0
  O  O23  1  0.781  0.703  0.525  1.0
  O  O24  1  0.054  0.500  0.315  1.0
  O  O25  1  0.553  0.500  0.815  1.0
  O  O26  1  0.447  0.001  0.187  1.0
  O  O27  1  0.944  1.000  0.685  1.0
  O  O28  1  0.895  0.500  0.037  1.0
  O  O29  1  0.396  0.500  0.534  1.0
  O  O30  1  0.600  1.000  0.466  1.0
  O  O31  1  0.099  0.000  0.967  1.0
  O  O32  1  0.040  0.999  0.319  1.0
  O  O33  1  0.542  0.000  0.820  1.0
  O  O34  1  0.462  0.500  0.180  1.0
  O  O35  1  0.962  0.500  0.679  1.0
  O  O36  1  0.212  0.770  0.458  1.0
  O  O37  1  0.711  0.770  0.959  1.0
  O  O38  1  0.916  0.227  0.165  1.0
  O  O39  1  0.418  0.229  0.665  1.0
  O  O40  1  0.287  0.276  0.041  1.0
  O  O41  1  0.787  0.276  0.540  1.0
  O  O42  1  0.585  0.726  0.335  1.0
  O  O43  1  0.083  0.724  0.836  1.0
[/CIF]
.