Sr2YNi2GaO7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 8-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(4), and three equivalent O(3) atoms. Y(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(4) atoms. Ni(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(4) atoms to form NiO5 trigonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra and corners with four equivalent Ni(1)O5 trigonal bipyramids. Ga(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form GaO4 tetrahedra that share corners with two equivalent Ga(1)O4 tetrahedra and corners with two equivalent Ni(1)O5 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ni(1) atoms to form distorted OSr2Y2Ni2 octahedra that share corners with four equivalent O(1)Sr2Y2Ni2 octahedra, corners with four equivalent O(4)Sr2Y2Ni2 octahedra, corners with two equivalent O(2)Sr2Ga2 tetrahedra, edges with three equivalent O(4)Sr2Y2Ni2 octahedra, faces with two equivalent O(1)Sr2Y2Ni2 octahedra, and faces with two equivalent O(4)Sr2Y2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-70°. In the second O site, O(2) is bonded to two equivalent Sr(1) and two equivalent Ga(1) atoms to form distorted OSr2Ga2 tetrahedra that share corners with four equivalent O(1)Sr2Y2Ni2 octahedra, corners with four equivalent O(4)Sr2Y2Ni2 octahedra, and corners with two equivalent O(2)Sr2Ga2 tetrahedra. The corner-sharing octahedral tilt angles range from 20-73°. In the third O site, O(3) is bonded in a 4-coordinate geometry to three equivalent Sr(1), one Ni(1), and one Ga(1) atom. In the fourth O site, O(4) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ni(1) atoms to form distorted OSr2Y2Ni2 octahedra that share corners with four equivalent O(1)Sr2Y2Ni2 octahedra, corners with four equivalent O(4)Sr2Y2Ni2 octahedra, corners with two equivalent O(2)Sr2Ga2 tetrahedra, edges with three equivalent O(1)Sr2Y2Ni2 octahedra, faces with two equivalent O(1)Sr2Y2Ni2 octahedra, and faces with two equivalent O(4)Sr2Y2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-70°.
Sr2YNi2GaO7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 8-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(4), and three equivalent O(3) atoms. The Sr(1)-O(2) bond length is 2.50 Å. There is one shorter (2.67 Å) and one longer (2.70 Å) Sr(1)-O(1) bond length. There is one shorter (2.75 Å) and one longer (2.77 Å) Sr(1)-O(4) bond length. There are a spread of Sr(1)-O(3) bond distances ranging from 2.52-2.98 Å. Y(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(4) atoms. There are two shorter (2.43 Å) and two longer (2.44 Å) Y(1)-O(1) bond lengths. There are two shorter (2.46 Å) and two longer (2.48 Å) Y(1)-O(4) bond lengths. Ni(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(4) atoms to form NiO5 trigonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra and corners with four equivalent Ni(1)O5 trigonal bipyramids. The Ni(1)-O(3) bond length is 2.10 Å. Both Ni(1)-O(1) bond lengths are 2.02 Å. Both Ni(1)-O(4) bond lengths are 2.00 Å. Ga(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form GaO4 tetrahedra that share corners with two equivalent Ga(1)O4 tetrahedra and corners with two equivalent Ni(1)O5 trigonal bipyramids. There is one shorter (1.90 Å) and one longer (1.91 Å) Ga(1)-O(2) bond length. Both Ga(1)-O(3) bond lengths are 1.86 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ni(1) atoms to form distorted OSr2Y2Ni2 octahedra that share corners with four equivalent O(1)Sr2Y2Ni2 octahedra, corners with four equivalent O(4)Sr2Y2Ni2 octahedra, corners with two equivalent O(2)Sr2Ga2 tetrahedra, edges with three equivalent O(4)Sr2Y2Ni2 octahedra, faces with two equivalent O(1)Sr2Y2Ni2 octahedra, and faces with two equivalent O(4)Sr2Y2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-70°. In the second O site, O(2) is bonded to two equivalent Sr(1) and two equivalent Ga(1) atoms to form distorted OSr2Ga2 tetrahedra that share corners with four equivalent O(1)Sr2Y2Ni2 octahedra, corners with four equivalent O(4)Sr2Y2Ni2 octahedra, and corners with two equivalent O(2)Sr2Ga2 tetrahedra. The corner-sharing octahedral tilt angles range from 20-73°. In the third O site, O(3) is bonded in a 4-coordinate geometry to three equivalent Sr(1), one Ni(1), and one Ga(1) atom. In the fourth O site, O(4) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ni(1) atoms to form distorted OSr2Y2Ni2 octahedra that share corners with four equivalent O(1)Sr2Y2Ni2 octahedra, corners with four equivalent O(4)Sr2Y2Ni2 octahedra, corners with two equivalent O(2)Sr2Ga2 tetrahedra, edges with three equivalent O(1)Sr2Y2Ni2 octahedra, faces with two equivalent O(1)Sr2Y2Ni2 octahedra, and faces with two equivalent O(4)Sr2Y2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-70°.