Ca4Al3O10 crystallizes in the triclinic P-1 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(4), one O(6), one O(9), and two equivalent O(3) atoms. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(1), one O(4), one O(6), one O(8), and two equivalent O(2) atoms. In the third Ca site, Ca(3) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(3), one O(4), one O(5), and two equivalent O(7) atoms. In the fourth Ca site, Ca(4) is bonded in a 7-coordinate geometry to one O(1), one O(8), one O(9), two equivalent O(2), and two equivalent O(5) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(10), one O(2), one O(3), one O(5), and one O(8) atom to form AlO5 trigonal bipyramids that share corners with two equivalent Al(2)O4 tetrahedra and  an edgeedge with one Al(3)O5 trigonal bipyramid. In the second Al site, Al(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form corner-sharing AlO4 tetrahedra. In the third Al site, Al(3) is bonded to one O(10), one O(4), one O(6), one O(8), and one O(9) atom to form AlO5 trigonal bipyramids that share  a cornercorner with one Al(2)O4 tetrahedra and  an edgeedge with one Al(1)O5 trigonal bipyramid. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(2), one Ca(3), one Ca(4), and one Al(2) atom to form distorted edge-sharing OCa4Al square pyramids. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ca(2), two equivalent Ca(4), one Al(1), and one Al(2) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Ca(3), two equivalent Ca(1), and one Al(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Ca(3), and one Al(3) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ca(3), two equivalent Ca(4), one Al(1), and one Al(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), one Ca(2), one Al(2), and one Al(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Ca(3) and one O(7) atom. In the eighth O site, O(8) is bonded to one Ca(2), one Ca(4), one Al(1), and one Al(3) atom to form distorted edge-sharing OCa2Al2 trigonal pyramids. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(4), and one Al(3) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), one Ca(3), one Al(1), and one Al(3) atom.
Ca4Al3O10 crystallizes in the triclinic P-1 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(4), one O(6), one O(9), and two equivalent O(3) atoms. The Ca(1)-O(1) bond length is 2.72 Å. The Ca(1)-O(10) bond length is 2.38 Å. The Ca(1)-O(4) bond length is 2.72 Å. The Ca(1)-O(6) bond length is 2.56 Å. The Ca(1)-O(9) bond length is 2.31 Å. There is one shorter (2.27 Å) and one longer (2.41 Å) Ca(1)-O(3) bond length. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(1), one O(4), one O(6), one O(8), and two equivalent O(2) atoms. The Ca(2)-O(1) bond length is 2.39 Å. The Ca(2)-O(4) bond length is 2.23 Å. The Ca(2)-O(6) bond length is 2.55 Å. The Ca(2)-O(8) bond length is 2.27 Å. There is one shorter (2.30 Å) and one longer (2.81 Å) Ca(2)-O(2) bond length. In the third Ca site, Ca(3) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(3), one O(4), one O(5), and two equivalent O(7) atoms. The Ca(3)-O(1) bond length is 2.38 Å. The Ca(3)-O(10) bond length is 2.28 Å. The Ca(3)-O(3) bond length is 2.41 Å. The Ca(3)-O(4) bond length is 2.38 Å. The Ca(3)-O(5) bond length is 2.94 Å. There is one shorter (2.38 Å) and one longer (2.39 Å) Ca(3)-O(7) bond length. In the fourth Ca site, Ca(4) is bonded in a 7-coordinate geometry to one O(1), one O(8), one O(9), two equivalent O(2), and two equivalent O(5) atoms. The Ca(4)-O(1) bond length is 2.64 Å. The Ca(4)-O(8) bond length is 2.38 Å. The Ca(4)-O(9) bond length is 2.25 Å. There is one shorter (2.65 Å) and one longer (2.89 Å) Ca(4)-O(2) bond length. There is one shorter (2.48 Å) and one longer (2.83 Å) Ca(4)-O(5) bond length. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(10), one O(2), one O(3), one O(5), and one O(8) atom to form AlO5 trigonal bipyramids that share corners with two equivalent Al(2)O4 tetrahedra and  an edgeedge with one Al(3)O5 trigonal bipyramid. The Al(1)-O(10) bond length is 1.89 Å. The Al(1)-O(2) bond length is 1.85 Å. The Al(1)-O(3) bond length is 1.84 Å. The Al(1)-O(5) bond length is 1.79 Å. The Al(1)-O(8) bond length is 1.94 Å. In the second Al site, Al(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom 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 1.80 Å. The Al(2)-O(5) bond length is 1.75 Å. The Al(2)-O(6) bond length is 1.75 Å. In the third Al site, Al(3) is bonded to one O(10), one O(4), one O(6), one O(8), and one O(9) atom to form AlO5 trigonal bipyramids that share  a cornercorner with one Al(2)O4 tetrahedra and  an edgeedge with one Al(1)O5 trigonal bipyramid. The Al(3)-O(10) bond length is 1.80 Å. The Al(3)-O(4) bond length is 1.80 Å. The Al(3)-O(6) bond length is 1.98 Å. The Al(3)-O(8) bond length is 1.84 Å. The Al(3)-O(9) bond length is 1.88 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(2), one Ca(3), one Ca(4), and one Al(2) atom to form distorted edge-sharing OCa4Al square pyramids. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ca(2), two equivalent Ca(4), one Al(1), and one Al(2) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Ca(3), two equivalent Ca(1), and one Al(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Ca(3), and one Al(3) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ca(3), two equivalent Ca(4), one Al(1), and one Al(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), one Ca(2), one Al(2), and one Al(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Ca(3) and one O(7) atom. The O(7)-O(7) bond length is 1.36 Å. In the eighth O site, O(8) is bonded to one Ca(2), one Ca(4), one Al(1), and one Al(3) atom to form distorted edge-sharing OCa2Al2 trigonal pyramids. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(4), and one Al(3) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), one Ca(3), one Al(1), and one Al(3) atom.