Gd3AsO7 crystallizes in the triclinic P-1 space group. There are three inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), one O(7), two equivalent O(2), and two equivalent O(6) atoms. In the second Gd site, Gd(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(5), one O(6), two equivalent O(4), and two equivalent O(7) atoms. In the third Gd site, Gd(3) is bonded to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one As(1)O6 octahedra,  a cornercorner with one As(2)O6 octahedra,  an edgeedge with one As(1)O6 octahedra,  an edgeedge with one As(2)O6 octahedra, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-43°. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form AsO6 octahedra that share corners with two equivalent As(2)O6 octahedra, corners with two equivalent Gd(3)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 37°. In the second As site, As(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form AsO6 octahedra that share corners with two equivalent As(1)O6 octahedra, corners with two equivalent Gd(3)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 37°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Gd(2), two equivalent Gd(3), and one As(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Gd(2), two equivalent Gd(1), and one As(1) atom. In the third O site, O(3) is bonded to one Gd(1), two equivalent Gd(3), and one As(1) atom to form distorted OGd3As trigonal pyramids that share  a cornercorner with one O(4)Gd3As tetrahedra,  a cornercorner with one O(7)Gd4 tetrahedra, corners with two equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3As trigonal pyramid,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(3)Gd3As trigonal pyramid. In the fourth O site, O(4) is bonded to one Gd(1), two equivalent Gd(2), and one As(2) atom to form distorted OGd3As tetrahedra that share  a cornercorner with one O(4)Gd3As tetrahedra, corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3As trigonal pyramid,  an edgeedge with one O(4)Gd3As tetrahedra, and  an edgeedge with one O(7)Gd4 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Gd(2), one Gd(3), one As(1), and one As(2) atom. In the sixth O site, O(6) is bonded to one Gd(2), one Gd(3), and two equivalent Gd(1) atoms to form OGd4 tetrahedra that share corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(4)Gd3As tetrahedra, corners with two equivalent O(3)Gd3As trigonal pyramids,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(3)Gd3As trigonal pyramid. In the seventh O site, O(7) is bonded to one Gd(1), one Gd(3), and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with three equivalent O(4)Gd3As tetrahedra, corners with three equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3As trigonal pyramid,  an edgeedge with one O(4)Gd3As tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(3)Gd3As trigonal pyramid.
Gd3AsO7 crystallizes in the triclinic P-1 space group. There are three inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), one O(7), two equivalent O(2), and two equivalent O(6) atoms. The Gd(1)-O(3) bond length is 2.57 Å. The Gd(1)-O(4) bond length is 2.37 Å. The Gd(1)-O(7) bond length is 2.28 Å. There is one shorter (2.37 Å) and one longer (2.50 Å) Gd(1)-O(2) bond length. There is one shorter (2.29 Å) and one longer (2.35 Å) Gd(1)-O(6) bond length. In the second Gd site, Gd(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(5), one O(6), two equivalent O(4), and two equivalent O(7) atoms. The Gd(2)-O(1) bond length is 2.89 Å. The Gd(2)-O(2) bond length is 2.63 Å. The Gd(2)-O(5) bond length is 2.72 Å. The Gd(2)-O(6) bond length is 2.29 Å. There is one shorter (2.44 Å) and one longer (2.56 Å) Gd(2)-O(4) bond length. There is one shorter (2.26 Å) and one longer (2.28 Å) Gd(2)-O(7) bond length. In the third Gd site, Gd(3) is bonded to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one As(1)O6 octahedra,  a cornercorner with one As(2)O6 octahedra,  an edgeedge with one As(1)O6 octahedra,  an edgeedge with one As(2)O6 octahedra, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-43°. The Gd(3)-O(5) bond length is 2.46 Å. The Gd(3)-O(6) bond length is 2.22 Å. The Gd(3)-O(7) bond length is 2.23 Å. There is one shorter (2.33 Å) and one longer (2.38 Å) Gd(3)-O(1) bond length. There is one shorter (2.37 Å) and one longer (2.40 Å) Gd(3)-O(3) bond length. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form AsO6 octahedra that share corners with two equivalent As(2)O6 octahedra, corners with two equivalent Gd(3)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 37°. Both As(1)-O(2) bond lengths are 1.87 Å. Both As(1)-O(3) bond lengths are 1.85 Å. Both As(1)-O(5) bond lengths are 1.98 Å. In the second As site, As(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form AsO6 octahedra that share corners with two equivalent As(1)O6 octahedra, corners with two equivalent Gd(3)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 37°. Both As(2)-O(1) bond lengths are 1.81 Å. Both As(2)-O(4) bond lengths are 1.93 Å. Both As(2)-O(5) bond lengths are 1.97 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Gd(2), two equivalent Gd(3), and one As(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Gd(2), two equivalent Gd(1), and one As(1) atom. In the third O site, O(3) is bonded to one Gd(1), two equivalent Gd(3), and one As(1) atom to form distorted OGd3As trigonal pyramids that share  a cornercorner with one O(4)Gd3As tetrahedra,  a cornercorner with one O(7)Gd4 tetrahedra, corners with two equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3As trigonal pyramid,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(3)Gd3As trigonal pyramid. In the fourth O site, O(4) is bonded to one Gd(1), two equivalent Gd(2), and one As(2) atom to form distorted OGd3As tetrahedra that share  a cornercorner with one O(4)Gd3As tetrahedra, corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3As trigonal pyramid,  an edgeedge with one O(4)Gd3As tetrahedra, and  an edgeedge with one O(7)Gd4 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Gd(2), one Gd(3), one As(1), and one As(2) atom. In the sixth O site, O(6) is bonded to one Gd(2), one Gd(3), and two equivalent Gd(1) atoms to form OGd4 tetrahedra that share corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(4)Gd3As tetrahedra, corners with two equivalent O(3)Gd3As trigonal pyramids,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(3)Gd3As trigonal pyramid. In the seventh O site, O(7) is bonded to one Gd(1), one Gd(3), and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with three equivalent O(4)Gd3As tetrahedra, corners with three equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3As trigonal pyramid,  an edgeedge with one O(4)Gd3As tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(3)Gd3As trigonal pyramid.