Li2SrNb2O7 crystallizes in the orthorhombic Cmcm space group. Li(1) is bonded to one O(1) and four equivalent O(3) atoms to form LiO5 trigonal bipyramids that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Li(1)O5 trigonal bipyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with four equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 64°. Sr(1) is bonded in a 12-coordinate geometry to four equivalent O(1), four equivalent O(2), and four equivalent O(4) atoms. Nb(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form NbO6 octahedra that share corners with five equivalent Nb(1)O6 octahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and edges with two equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 1-21°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Li(1), two equivalent Sr(1), and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded to two equivalent Sr(1) and two equivalent Nb(1) atoms to form distorted OSr2Nb2 trigonal pyramids that share corners with two equivalent O(3)Li4Nb trigonal bipyramids, corners with two equivalent O(2)Sr2Nb2 trigonal pyramids, and edges with three equivalent O(2)Sr2Nb2 trigonal pyramids. In the third O site, O(3) is bonded to four equivalent Li(1) and one Nb(1) atom to form distorted OLi4Nb trigonal bipyramids that share corners with four equivalent O(3)Li4Nb trigonal bipyramids, corners with two equivalent O(2)Sr2Nb2 trigonal pyramids, and edges with four equivalent O(3)Li4Nb trigonal bipyramids. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to four equivalent Sr(1) and two equivalent Nb(1) atoms.
Li2SrNb2O7 crystallizes in the orthorhombic Cmcm space group. Li(1) is bonded to one O(1) and four equivalent O(3) atoms to form LiO5 trigonal bipyramids that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Li(1)O5 trigonal bipyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with four equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 64°. The Li(1)-O(1) bond length is 2.24 Å. There are two shorter (2.05 Å) and two longer (2.17 Å) Li(1)-O(3) bond lengths. Sr(1) is bonded in a 12-coordinate geometry to four equivalent O(1), four equivalent O(2), and four equivalent O(4) atoms. All Sr(1)-O(1) bond lengths are 2.91 Å. All Sr(1)-O(2) bond lengths are 2.67 Å. There are a spread of Sr(1)-O(4) bond distances ranging from 2.54-3.13 Å. Nb(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form NbO6 octahedra that share corners with five equivalent Nb(1)O6 octahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and edges with two equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 1-21°. The Nb(1)-O(3) bond length is 1.89 Å. The Nb(1)-O(4) bond length is 2.14 Å. Both Nb(1)-O(1) bond lengths are 2.02 Å. Both Nb(1)-O(2) bond lengths are 2.03 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Li(1), two equivalent Sr(1), and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded to two equivalent Sr(1) and two equivalent Nb(1) atoms to form distorted OSr2Nb2 trigonal pyramids that share corners with two equivalent O(3)Li4Nb trigonal bipyramids, corners with two equivalent O(2)Sr2Nb2 trigonal pyramids, and edges with three equivalent O(2)Sr2Nb2 trigonal pyramids. In the third O site, O(3) is bonded to four equivalent Li(1) and one Nb(1) atom to form distorted OLi4Nb trigonal bipyramids that share corners with four equivalent O(3)Li4Nb trigonal bipyramids, corners with two equivalent O(2)Sr2Nb2 trigonal pyramids, and edges with four equivalent O(3)Li4Nb trigonal bipyramids. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to four equivalent Sr(1) and two equivalent Nb(1) atoms.