The crystal structure described by MgAlSi4O13O2 crystallizes in the monoclinic C2/m space group. The structure consists of eight water atoms inside a MgAlSi4O13 framework. In the MgAlSi4O13 framework, Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms to form distorted MgO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. Al(1) is bonded in a 6-coordinate geometry to two equivalent O(10), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(7), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. In the second Si site, Si(2) is bonded to one O(3), one O(5), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are eight inequivalent O sites. In the first O site, O(5) is bonded in a linear geometry to two equivalent Si(2) atoms. In the second O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one O(6) atom. In the third O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fourth O site, O(8) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(9) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(10) is bonded in a 2-coordinate geometry to one Al(1) and one O(10) atom. In the seventh O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Al(1), and one Si(1) atom. In the eighth O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Al(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgAlSi4O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.142
_cell_length_b   11.142
_cell_length_c   5.284
_cell_angle_alpha   84.204
_cell_angle_beta   84.204
_cell_angle_gamma   104.743
_symmetry_Int_Tables_number   1
_cell_volume   625.667
_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  0.111  0.889  0.500  1.0
  Mg  Mg1  1  0.889  0.111  0.500  1.0
  Al  Al2  1  0.165  0.835  0.000  1.0
  Al  Al3  1  0.835  0.165  0.000  1.0
  Si  Si4  1  0.294  0.115  0.112  1.0
  Si  Si5  1  0.115  0.294  0.112  1.0
  Si  Si6  1  0.706  0.885  0.888  1.0
  Si  Si7  1  0.885  0.706  0.888  1.0
  Si  Si8  1  0.379  0.042  0.615  1.0
  Si  Si9  1  0.042  0.379  0.615  1.0
  Si  Si10  1  0.621  0.958  0.385  1.0
  Si  Si11  1  0.958  0.621  0.385  1.0
  O  O12  1  0.383  0.617  0.500  1.0
  O  O13  1  0.617  0.383  0.500  1.0
  O  O14  1  0.199  0.973  0.159  1.0
  O  O15  1  0.973  0.199  0.159  1.0
  O  O16  1  0.801  0.027  0.841  1.0
  O  O17  1  0.027  0.801  0.841  1.0
  O  O18  1  0.259  0.917  0.695  1.0
  O  O19  1  0.917  0.259  0.695  1.0
  O  O20  1  0.741  0.083  0.305  1.0
  O  O21  1  0.083  0.741  0.305  1.0
  O  O22  1  0.409  0.591  0.000  1.0
  O  O23  1  0.591  0.409  0.000  1.0
  O  O24  1  0.500  0.000  0.500  1.0
  O  O25  1  0.000  0.500  0.500  1.0
  O  O26  1  0.042  0.042  0.557  1.0
  O  O27  1  0.958  0.958  0.443  1.0
  O  O28  1  0.221  0.221  0.044  1.0
  O  O29  1  0.779  0.779  0.956  1.0
  O  O30  1  0.400  0.115  0.869  1.0
  O  O31  1  0.115  0.400  0.869  1.0
  O  O32  1  0.600  0.885  0.131  1.0
  O  O33  1  0.885  0.600  0.131  1.0
  O  O34  1  0.350  0.136  0.383  1.0
  O  O35  1  0.136  0.350  0.383  1.0
  O  O36  1  0.650  0.864  0.617  1.0
  O  O37  1  0.864  0.650  0.617  1.0
  O  O38  1  0.322  0.754  0.059  1.0
  O  O39  1  0.754  0.322  0.059  1.0
  O  O40  1  0.678  0.246  0.941  1.0
  O  O41  1  0.246  0.678  0.941  1.0
[/CIF]
.
The crystal structure described by MgAlSi4O13O2 crystallizes in the monoclinic C2/m space group. The structure consists of eight water atoms inside a MgAlSi4O13 framework. In the MgAlSi4O13 framework, Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms to form distorted MgO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. Al(1) is bonded in a 6-coordinate geometry to two equivalent O(10), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(7), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. In the second Si site, Si(2) is bonded to one O(3), one O(5), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are eight inequivalent O sites. In the first O site, O(5) is bonded in a linear geometry to two equivalent Si(2) atoms. In the second O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one O(6) atom. In the third O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fourth O site, O(8) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(9) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(10) is bonded in a 2-coordinate geometry to one Al(1) and one O(10) atom. In the seventh O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Al(1), and one Si(1) atom. In the eighth O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Al(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgAlSi4O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.142
_cell_length_b   11.142
_cell_length_c   5.284
_cell_angle_alpha   84.204
_cell_angle_beta   84.204
_cell_angle_gamma   104.743
_symmetry_Int_Tables_number   1
_cell_volume   625.667
_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  0.111  0.889  0.500  1.0
  Mg  Mg1  1  0.889  0.111  0.500  1.0
  Al  Al2  1  0.165  0.835  0.000  1.0
  Al  Al3  1  0.835  0.165  0.000  1.0
  Si  Si4  1  0.294  0.115  0.112  1.0
  Si  Si5  1  0.115  0.294  0.112  1.0
  Si  Si6  1  0.706  0.885  0.888  1.0
  Si  Si7  1  0.885  0.706  0.888  1.0
  Si  Si8  1  0.379  0.042  0.615  1.0
  Si  Si9  1  0.042  0.379  0.615  1.0
  Si  Si10  1  0.621  0.958  0.385  1.0
  Si  Si11  1  0.958  0.621  0.385  1.0
  O  O12  1  0.383  0.617  0.500  1.0
  O  O13  1  0.617  0.383  0.500  1.0
  O  O14  1  0.199  0.973  0.159  1.0
  O  O15  1  0.973  0.199  0.159  1.0
  O  O16  1  0.801  0.027  0.841  1.0
  O  O17  1  0.027  0.801  0.841  1.0
  O  O18  1  0.259  0.917  0.695  1.0
  O  O19  1  0.917  0.259  0.695  1.0
  O  O20  1  0.741  0.083  0.305  1.0
  O  O21  1  0.083  0.741  0.305  1.0
  O  O22  1  0.409  0.591  0.000  1.0
  O  O23  1  0.591  0.409  0.000  1.0
  O  O24  1  0.500  0.000  0.500  1.0
  O  O25  1  0.000  0.500  0.500  1.0
  O  O26  1  0.042  0.042  0.557  1.0
  O  O27  1  0.958  0.958  0.443  1.0
  O  O28  1  0.221  0.221  0.044  1.0
  O  O29  1  0.779  0.779  0.956  1.0
  O  O30  1  0.400  0.115  0.869  1.0
  O  O31  1  0.115  0.400  0.869  1.0
  O  O32  1  0.600  0.885  0.131  1.0
  O  O33  1  0.885  0.600  0.131  1.0
  O  O34  1  0.350  0.136  0.383  1.0
  O  O35  1  0.136  0.350  0.383  1.0
  O  O36  1  0.650  0.864  0.617  1.0
  O  O37  1  0.864  0.650  0.617  1.0
  O  O38  1  0.322  0.754  0.059  1.0
  O  O39  1  0.754  0.322  0.059  1.0
  O  O40  1  0.678  0.246  0.941  1.0
  O  O41  1  0.246  0.678  0.941  1.0
[/CIF]
.