The material described by MgAl2(PO4)3 is Keatite-derived structured and crystallizes in the monoclinic Cc space group. Mg(1) is bonded to one O(11), one O(6), one O(8), and one O(9) atom to form MgO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(10), one O(4), and one O(7) atom to form AlO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(3)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(12), one O(2), one O(3), and one O(5) atom to form AlO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(12), one O(4), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. In the second P site, P(2) is bonded to one O(11), one O(2), one O(5), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O4 tetrahedra and corners with two equivalent Al(2)O4 tetrahedra. In the third P site, P(3) is bonded to one O(1), one O(10), one O(3), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(9) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(1) atom. In the second O site, O(10) is bonded in a bent 150 degrees geometry to one Al(1) and one P(3) atom. In the third O site, O(11) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(2) atom. In the fourth O site, O(12) is bonded in a bent 150 degrees geometry to one Al(2) and one P(1) atom. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one Al(1) and one P(3) atom. In the sixth O site, O(2) is bonded in a linear geometry to one Al(2) and one P(2) atom. In the seventh O site, O(3) is bonded in a bent 150 degrees geometry to one Al(2) and one P(3) atom. In the eighth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(1) and one P(1) atom. In the ninth O site, O(5) is bonded in a bent 150 degrees geometry to one Al(2) and one P(2) atom. In the tenth O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(3) atom. In the eleventh O site, O(7) is bonded in a bent 150 degrees geometry to one Al(1) and one P(1) atom. In the twelfth O site, O(8) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(2) atom. is represented by the CIF card [CIF]
data_MgAl2(PO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.330
_cell_length_b   9.330
_cell_length_c   9.193
_cell_angle_alpha   89.994
_cell_angle_beta   89.994
_cell_angle_gamma   89.156
_symmetry_Int_Tables_number   1
_cell_volume   800.160
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Mg  Mg0  1  0.743  0.997  1.000  1.0
  Mg  Mg1  1  0.997  0.743  0.500  1.0
  Al  Al2  1  0.497  0.498  0.250  1.0
  Al  Al3  1  0.004  0.256  0.500  1.0
  Al  Al4  1  0.498  0.497  0.750  1.0
  Al  Al5  1  0.256  0.004  1.000  1.0
  P  P6  1  0.744  0.492  0.499  1.0
  P  P7  1  0.492  0.744  0.999  1.0
  P  P8  1  0.011  0.010  0.250  1.0
  P  P9  1  0.493  0.255  0.001  1.0
  P  P10  1  0.010  0.011  0.750  1.0
  P  P11  1  0.255  0.493  0.501  1.0
  O  O12  1  0.493  0.348  0.863  1.0
  O  O13  1  0.144  0.007  0.848  1.0
  O  O14  1  0.157  0.361  0.495  1.0
  O  O15  1  0.492  0.650  0.138  1.0
  O  O16  1  0.144  0.019  0.152  1.0
  O  O17  1  0.168  0.630  0.507  1.0
  O  O18  1  0.481  0.649  0.862  1.0
  O  O19  1  0.871  0.020  0.838  1.0
  O  O20  1  0.830  0.629  0.493  1.0
  O  O21  1  0.480  0.349  0.137  1.0
  O  O22  1  0.872  0.005  0.163  1.0
  O  O23  1  0.844  0.358  0.505  1.0
  O  O24  1  0.348  0.493  0.363  1.0
  O  O25  1  0.007  0.144  0.348  1.0
  O  O26  1  0.361  0.157  0.995  1.0
  O  O27  1  0.650  0.492  0.638  1.0
  O  O28  1  0.019  0.144  0.652  1.0
  O  O29  1  0.630  0.168  0.007  1.0
  O  O30  1  0.649  0.481  0.362  1.0
  O  O31  1  0.020  0.871  0.338  1.0
  O  O32  1  0.629  0.830  0.993  1.0
  O  O33  1  0.349  0.480  0.637  1.0
  O  O34  1  0.005  0.872  0.663  1.0
  O  O35  1  0.358  0.844  0.005  1.0
[/CIF]
.
The material described by MgAl2(PO4)3 is Keatite-derived structured and crystallizes in the monoclinic Cc space group. Mg(1) is bonded to one O(11), one O(6), one O(8), and one O(9) atom to form MgO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(10), one O(4), and one O(7) atom to form AlO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(3)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(12), one O(2), one O(3), and one O(5) atom to form AlO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(12), one O(4), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. In the second P site, P(2) is bonded to one O(11), one O(2), one O(5), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O4 tetrahedra and corners with two equivalent Al(2)O4 tetrahedra. In the third P site, P(3) is bonded to one O(1), one O(10), one O(3), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(9) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(1) atom. In the second O site, O(10) is bonded in a bent 150 degrees geometry to one Al(1) and one P(3) atom. In the third O site, O(11) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(2) atom. In the fourth O site, O(12) is bonded in a bent 150 degrees geometry to one Al(2) and one P(1) atom. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one Al(1) and one P(3) atom. In the sixth O site, O(2) is bonded in a linear geometry to one Al(2) and one P(2) atom. In the seventh O site, O(3) is bonded in a bent 150 degrees geometry to one Al(2) and one P(3) atom. In the eighth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(1) and one P(1) atom. In the ninth O site, O(5) is bonded in a bent 150 degrees geometry to one Al(2) and one P(2) atom. In the tenth O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(3) atom. In the eleventh O site, O(7) is bonded in a bent 150 degrees geometry to one Al(1) and one P(1) atom. In the twelfth O site, O(8) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(2) atom. is represented by the CIF card [CIF]
data_MgAl2(PO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.330
_cell_length_b   9.330
_cell_length_c   9.193
_cell_angle_alpha   89.994
_cell_angle_beta   89.994
_cell_angle_gamma   89.156
_symmetry_Int_Tables_number   1
_cell_volume   800.160
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Mg  Mg0  1  0.743  0.997  1.000  1.0
  Mg  Mg1  1  0.997  0.743  0.500  1.0
  Al  Al2  1  0.497  0.498  0.250  1.0
  Al  Al3  1  0.004  0.256  0.500  1.0
  Al  Al4  1  0.498  0.497  0.750  1.0
  Al  Al5  1  0.256  0.004  1.000  1.0
  P  P6  1  0.744  0.492  0.499  1.0
  P  P7  1  0.492  0.744  0.999  1.0
  P  P8  1  0.011  0.010  0.250  1.0
  P  P9  1  0.493  0.255  0.001  1.0
  P  P10  1  0.010  0.011  0.750  1.0
  P  P11  1  0.255  0.493  0.501  1.0
  O  O12  1  0.493  0.348  0.863  1.0
  O  O13  1  0.144  0.007  0.848  1.0
  O  O14  1  0.157  0.361  0.495  1.0
  O  O15  1  0.492  0.650  0.138  1.0
  O  O16  1  0.144  0.019  0.152  1.0
  O  O17  1  0.168  0.630  0.507  1.0
  O  O18  1  0.481  0.649  0.862  1.0
  O  O19  1  0.871  0.020  0.838  1.0
  O  O20  1  0.830  0.629  0.493  1.0
  O  O21  1  0.480  0.349  0.137  1.0
  O  O22  1  0.872  0.005  0.163  1.0
  O  O23  1  0.844  0.358  0.505  1.0
  O  O24  1  0.348  0.493  0.363  1.0
  O  O25  1  0.007  0.144  0.348  1.0
  O  O26  1  0.361  0.157  0.995  1.0
  O  O27  1  0.650  0.492  0.638  1.0
  O  O28  1  0.019  0.144  0.652  1.0
  O  O29  1  0.630  0.168  0.007  1.0
  O  O30  1  0.649  0.481  0.362  1.0
  O  O31  1  0.020  0.871  0.338  1.0
  O  O32  1  0.629  0.830  0.993  1.0
  O  O33  1  0.349  0.480  0.637  1.0
  O  O34  1  0.005  0.872  0.663  1.0
  O  O35  1  0.358  0.844  0.005  1.0
[/CIF]
.