BaCaAl3P2(HO7)2 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a 12-coordinate geometry to one H(1), one H(2), one O(3), one O(4), two equivalent O(10), two equivalent O(5), two equivalent O(6), and two equivalent O(9) atoms. Ca(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), and two equivalent O(10) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(3), one O(4), two equivalent O(10), and two equivalent O(9) atoms to form distorted AlO6 octahedra that share corners with four equivalent Al(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-53°. In the second Al site, Al(2) is bonded to one O(10), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted AlO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-58°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), and two equivalent O(5) atoms to form PO4 tetrahedra that share  a cornercorner with one Al(1)O6 octahedra and corners with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-57°. In the second P site, P(2) is bonded to one O(2), one O(4), and two equivalent O(6) atoms to form PO4 tetrahedra that share  a cornercorner with one Al(1)O6 octahedra and corners with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-47°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Ba(1) and one O(7) atom. In the second H site, H(2) is bonded in a single-bond geometry to one Ba(1) and one O(8) atom. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ca(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to one Ca(1) and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one Al(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(1), one Al(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Ba(1), one Al(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Al(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to two equivalent Al(2) and one H(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Al(2) and one H(2) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Ba(1), one Al(1), one Al(2), and one O(9) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Ba(1), one Ca(1), one Al(1), and one Al(2) atom.
BaCaAl3P2(HO7)2 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a 12-coordinate geometry to one H(1), one H(2), one O(3), one O(4), two equivalent O(10), two equivalent O(5), two equivalent O(6), and two equivalent O(9) atoms. The Ba(1)-H(1) bond length is 2.94 Å. The Ba(1)-H(2) bond length is 3.04 Å. The Ba(1)-O(3) bond length is 2.94 Å. The Ba(1)-O(4) bond length is 2.72 Å. Both Ba(1)-O(10) bond lengths are 2.79 Å. Both Ba(1)-O(5) bond lengths are 3.04 Å. Both Ba(1)-O(6) bond lengths are 3.01 Å. Both Ba(1)-O(9) bond lengths are 2.80 Å. Ca(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), and two equivalent O(10) atoms. The Ca(1)-O(1) bond length is 2.23 Å. The Ca(1)-O(2) bond length is 2.38 Å. Both Ca(1)-O(10) bond lengths are 2.35 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(3), one O(4), two equivalent O(10), and two equivalent O(9) atoms to form distorted AlO6 octahedra that share corners with four equivalent Al(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-53°. The Al(1)-O(3) bond length is 1.91 Å. The Al(1)-O(4) bond length is 1.95 Å. Both Al(1)-O(10) bond lengths are 1.75 Å. Both Al(1)-O(9) bond lengths are 1.97 Å. In the second Al site, Al(2) is bonded to one O(10), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted AlO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-58°. The Al(2)-O(10) bond length is 1.78 Å. The Al(2)-O(5) bond length is 1.86 Å. The Al(2)-O(6) bond length is 1.86 Å. The Al(2)-O(7) bond length is 1.95 Å. The Al(2)-O(8) bond length is 1.86 Å. The Al(2)-O(9) bond length is 2.30 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), and two equivalent O(5) atoms to form PO4 tetrahedra that share  a cornercorner with one Al(1)O6 octahedra and corners with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-57°. The P(1)-O(1) bond length is 1.50 Å. The P(1)-O(3) bond length is 1.55 Å. Both P(1)-O(5) bond lengths are 1.55 Å. In the second P site, P(2) is bonded to one O(2), one O(4), and two equivalent O(6) atoms to form PO4 tetrahedra that share  a cornercorner with one Al(1)O6 octahedra and corners with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-47°. The P(2)-O(2) bond length is 1.51 Å. The P(2)-O(4) bond length is 1.54 Å. Both P(2)-O(6) bond lengths are 1.56 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Ba(1) and one O(7) atom. The H(1)-O(7) bond length is 0.99 Å. In the second H site, H(2) is bonded in a single-bond geometry to one Ba(1) and one O(8) atom. The H(2)-O(8) bond length is 0.98 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ca(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to one Ca(1) and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one Al(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(1), one Al(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Ba(1), one Al(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Al(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to two equivalent Al(2) and one H(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Al(2) and one H(2) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Ba(1), one Al(1), one Al(2), and one O(9) atom. The O(9)-O(9) bond length is 1.39 Å. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Ba(1), one Ca(1), one Al(1), and one Al(2) atom.