LiSr4Mn2(GaO5)2 crystallizes in the monoclinic C2/m space group. Li(1) is bonded in a distorted linear geometry to two equivalent O(4) atoms. Sr(1) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra and corners with two equivalent Ga(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 2-6°. Ga(1) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form distorted GaO4 trigonal pyramids that share corners with two equivalent Mn(1)O6 octahedra and  an edgeedge with one Ga(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 35°. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1) and two equivalent Mn(1) atoms to form distorted OSr4Mn2 octahedra that share corners with two equivalent O(1)Sr4Mn2 octahedra, corners with four equivalent O(4)Sr2LiGa2 trigonal bipyramids, edges with two equivalent O(1)Sr4Mn2 octahedra, and faces with four equivalent O(2)Sr4Mn2 octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to four equivalent Sr(1) and two equivalent Mn(1) atoms to form distorted OSr4Mn2 octahedra that share corners with two equivalent O(2)Sr4Mn2 octahedra, corners with four equivalent O(4)Sr2LiGa2 trigonal bipyramids, edges with two equivalent O(2)Sr4Mn2 octahedra, and faces with four equivalent O(1)Sr4Mn2 octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded in a 1-coordinate geometry to two equivalent Sr(1), one Mn(1), and one Ga(1) atom. In the fourth O site, O(4) is bonded to one Li(1), two equivalent Sr(1), and two equivalent Ga(1) atoms to form distorted OSr2LiGa2 trigonal bipyramids that share corners with four equivalent O(1)Sr4Mn2 octahedra, corners with four equivalent O(2)Sr4Mn2 octahedra,  a cornercorner with one O(4)Sr2LiGa2 trigonal bipyramid, and  an edgeedge with one O(4)Sr2LiGa2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 28-72°.
LiSr4Mn2(GaO5)2 crystallizes in the monoclinic C2/m space group. Li(1) is bonded in a distorted linear geometry to two equivalent O(4) atoms. Both Li(1)-O(4) bond lengths are 2.03 Å. Sr(1) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Sr(1)-O(4) bond length is 2.52 Å. There is one shorter (2.61 Å) and one longer (2.69 Å) Sr(1)-O(1) bond length. There is one shorter (2.62 Å) and one longer (2.65 Å) Sr(1)-O(2) bond length. There is one shorter (2.67 Å) and one longer (2.76 Å) Sr(1)-O(3) bond length. Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra and corners with two equivalent Ga(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 2-6°. Both Mn(1)-O(1) bond lengths are 2.01 Å. Both Mn(1)-O(2) bond lengths are 2.03 Å. Both Mn(1)-O(3) bond lengths are 2.51 Å. Ga(1) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form distorted GaO4 trigonal pyramids that share corners with two equivalent Mn(1)O6 octahedra and  an edgeedge with one Ga(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 35°. Both Ga(1)-O(3) bond lengths are 1.83 Å. There is one shorter (1.89 Å) and one longer (2.07 Å) Ga(1)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1) and two equivalent Mn(1) atoms to form distorted OSr4Mn2 octahedra that share corners with two equivalent O(1)Sr4Mn2 octahedra, corners with four equivalent O(4)Sr2LiGa2 trigonal bipyramids, edges with two equivalent O(1)Sr4Mn2 octahedra, and faces with four equivalent O(2)Sr4Mn2 octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to four equivalent Sr(1) and two equivalent Mn(1) atoms to form distorted OSr4Mn2 octahedra that share corners with two equivalent O(2)Sr4Mn2 octahedra, corners with four equivalent O(4)Sr2LiGa2 trigonal bipyramids, edges with two equivalent O(2)Sr4Mn2 octahedra, and faces with four equivalent O(1)Sr4Mn2 octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded in a 1-coordinate geometry to two equivalent Sr(1), one Mn(1), and one Ga(1) atom. In the fourth O site, O(4) is bonded to one Li(1), two equivalent Sr(1), and two equivalent Ga(1) atoms to form distorted OSr2LiGa2 trigonal bipyramids that share corners with four equivalent O(1)Sr4Mn2 octahedra, corners with four equivalent O(2)Sr4Mn2 octahedra,  a cornercorner with one O(4)Sr2LiGa2 trigonal bipyramid, and  an edgeedge with one O(4)Sr2LiGa2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 28-72°.