SrAl4O7 crystallizes in the monoclinic C2/c space group. Sr(1) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(2), and four equivalent O(3) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form corner-sharing AlO4 tetrahedra. In the second Al site, Al(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form corner-sharing AlO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Al(2) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Sr(1), one Al(1), and one Al(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Sr(1) and two equivalent Al(2) atoms. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Sr(1) and two equivalent Al(1) atoms.
SrAl4O7 crystallizes in the monoclinic C2/c space group. Sr(1) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(2), and four equivalent O(3) atoms. The Sr(1)-O(4) bond length is 2.58 Å. Both Sr(1)-O(2) bond lengths are 2.53 Å. There are two shorter (2.56 Å) and two longer (2.81 Å) Sr(1)-O(3) bond lengths. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form corner-sharing AlO4 tetrahedra. The Al(1)-O(2) bond length is 1.72 Å. The Al(1)-O(4) bond length is 1.74 Å. There is one shorter (1.79 Å) and one longer (1.81 Å) Al(1)-O(1) bond length. In the second Al site, Al(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form corner-sharing AlO4 tetrahedra. The Al(2)-O(1) bond length is 1.79 Å. The Al(2)-O(2) bond length is 1.73 Å. There is one shorter (1.75 Å) and one longer (1.76 Å) Al(2)-O(3) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Al(2) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Sr(1), one Al(1), and one Al(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Sr(1) and two equivalent Al(2) atoms. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Sr(1) and two equivalent Al(1) atoms.