Li3Sr2TaN4 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form distorted LiN4 tetrahedra that share corners with two equivalent Sr(1)N6 octahedra, corners with four equivalent Sr(2)N6 octahedra, corners with two equivalent Li(1)N4 tetrahedra, corners with two equivalent Ta(1)N4 tetrahedra,  an edgeedge with one Sr(2)N6 octahedra, edges with two equivalent Sr(1)N6 octahedra,  an edgeedge with one Li(1)N4 tetrahedra, and  an edgeedge with one Ta(1)N4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-58°. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one N(2), one N(3), and two equivalent N(1) atoms. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one N(2), one N(3), and four equivalent N(1) atoms to form distorted SrN6 octahedra that share corners with four equivalent Sr(1)N6 octahedra, corners with four equivalent Li(1)N4 tetrahedra, corners with four equivalent Ta(1)N4 tetrahedra, edges with four equivalent Sr(2)N6 octahedra,  an edgeedge with one Ta(1)N4 tetrahedra, and edges with four equivalent Li(1)N4 tetrahedra. The corner-sharing octahedral tilt angles are 19°. In the second Sr site, Sr(2) is bonded to two equivalent N(1), two equivalent N(2), and two equivalent N(3) atoms to form distorted SrN6 octahedra that share corners with two equivalent Ta(1)N4 tetrahedra, corners with eight equivalent Li(1)N4 tetrahedra, edges with two equivalent Sr(2)N6 octahedra, edges with four equivalent Sr(1)N6 octahedra, edges with two equivalent Li(1)N4 tetrahedra, and edges with two equivalent Ta(1)N4 tetrahedra. Ta(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form TaN4 tetrahedra that share corners with two equivalent Sr(2)N6 octahedra, corners with four equivalent Sr(1)N6 octahedra, corners with four equivalent Li(1)N4 tetrahedra,  an edgeedge with one Sr(1)N6 octahedra, edges with two equivalent Sr(2)N6 octahedra, and edges with two equivalent Li(1)N4 tetrahedra. The corner-sharing octahedral tilt angles range from 17-82°. There are three inequivalent N sites. In the first N site, N(2) is bonded in a 7-coordinate geometry to one Li(2), two equivalent Li(1), one Sr(1), two equivalent Sr(2), and one Ta(1) atom. In the second N site, N(3) is bonded in a 7-coordinate geometry to one Li(2), two equivalent Li(1), one Sr(1), two equivalent Sr(2), and one Ta(1) atom. In the third N site, N(1) is bonded in a 7-coordinate geometry to one Li(2), two equivalent Li(1), one Sr(2), two equivalent Sr(1), and one Ta(1) atom.
Li3Sr2TaN4 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form distorted LiN4 tetrahedra that share corners with two equivalent Sr(1)N6 octahedra, corners with four equivalent Sr(2)N6 octahedra, corners with two equivalent Li(1)N4 tetrahedra, corners with two equivalent Ta(1)N4 tetrahedra,  an edgeedge with one Sr(2)N6 octahedra, edges with two equivalent Sr(1)N6 octahedra,  an edgeedge with one Li(1)N4 tetrahedra, and  an edgeedge with one Ta(1)N4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-58°. The Li(1)-N(2) bond length is 2.18 Å. The Li(1)-N(3) bond length is 2.36 Å. There is one shorter (2.10 Å) and one longer (2.17 Å) Li(1)-N(1) bond length. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one N(2), one N(3), and two equivalent N(1) atoms. The Li(2)-N(2) bond length is 2.16 Å. The Li(2)-N(3) bond length is 2.49 Å. Both Li(2)-N(1) bond lengths are 2.07 Å. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one N(2), one N(3), and four equivalent N(1) atoms to form distorted SrN6 octahedra that share corners with four equivalent Sr(1)N6 octahedra, corners with four equivalent Li(1)N4 tetrahedra, corners with four equivalent Ta(1)N4 tetrahedra, edges with four equivalent Sr(2)N6 octahedra,  an edgeedge with one Ta(1)N4 tetrahedra, and edges with four equivalent Li(1)N4 tetrahedra. The corner-sharing octahedral tilt angles are 19°. The Sr(1)-N(2) bond length is 2.78 Å. The Sr(1)-N(3) bond length is 2.69 Å. There are two shorter (2.86 Å) and two longer (2.95 Å) Sr(1)-N(1) bond lengths. In the second Sr site, Sr(2) is bonded to two equivalent N(1), two equivalent N(2), and two equivalent N(3) atoms to form distorted SrN6 octahedra that share corners with two equivalent Ta(1)N4 tetrahedra, corners with eight equivalent Li(1)N4 tetrahedra, edges with two equivalent Sr(2)N6 octahedra, edges with four equivalent Sr(1)N6 octahedra, edges with two equivalent Li(1)N4 tetrahedra, and edges with two equivalent Ta(1)N4 tetrahedra. Both Sr(2)-N(1) bond lengths are 2.65 Å. Both Sr(2)-N(2) bond lengths are 2.79 Å. Both Sr(2)-N(3) bond lengths are 2.62 Å. Ta(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form TaN4 tetrahedra that share corners with two equivalent Sr(2)N6 octahedra, corners with four equivalent Sr(1)N6 octahedra, corners with four equivalent Li(1)N4 tetrahedra,  an edgeedge with one Sr(1)N6 octahedra, edges with two equivalent Sr(2)N6 octahedra, and edges with two equivalent Li(1)N4 tetrahedra. The corner-sharing octahedral tilt angles range from 17-82°. The Ta(1)-N(2) bond length is 2.00 Å. The Ta(1)-N(3) bond length is 1.97 Å. Both Ta(1)-N(1) bond lengths are 1.97 Å. There are three inequivalent N sites. In the first N site, N(2) is bonded in a 7-coordinate geometry to one Li(2), two equivalent Li(1), one Sr(1), two equivalent Sr(2), and one Ta(1) atom. In the second N site, N(3) is bonded in a 7-coordinate geometry to one Li(2), two equivalent Li(1), one Sr(1), two equivalent Sr(2), and one Ta(1) atom. In the third N site, N(1) is bonded in a 7-coordinate geometry to one Li(2), two equivalent Li(1), one Sr(2), two equivalent Sr(1), and one Ta(1) atom.