The material described by CaAl2Si2O7(OH)2H2O crystallizes in the orthorhombic Cmcm space group. The structure consists of four water molecules inside a CaAl2Si2O7(OH)2 framework. In the CaAl2Si2O7(OH)2 framework, Ca(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted CaO5 trigonal bipyramids that share corners with four equivalent Al(1)O6 octahedra and corners with six equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. Al(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with two equivalent Ca(1)O5 trigonal bipyramids, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with three equivalent Ca(1)O5 trigonal bipyramids, and edges with two equivalent Al(1)O6 octahedra. H(2) is bonded in a single-bond geometry to one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ca(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Al(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Al(1) and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Al(1) and one H(2) atom. is represented by the CIF file [CIF]
data_CaAl2Si2(H2O5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.804
_cell_length_b   5.804
_cell_length_c   14.066
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   118.788
_symmetry_Int_Tables_number   1
_cell_volume   415.284
_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
  Ca  Ca0  1  0.897  0.103  0.250  1.0
  Ca  Ca1  1  0.103  0.897  0.750  1.0
  Al  Al2  1  0.500  0.000  0.500  1.0
  Al  Al3  1  0.000  0.500  0.500  1.0
  Al  Al4  1  0.500  0.000  0.000  1.0
  Al  Al5  1  0.000  0.500  0.000  1.0
  Si  Si6  1  0.243  0.757  0.350  1.0
  Si  Si7  1  0.757  0.243  0.650  1.0
  Si  Si8  1  0.243  0.757  0.150  1.0
  Si  Si9  1  0.757  0.243  0.850  1.0
  H  H10  1  0.518  0.482  0.305  1.0
  H  H11  1  0.482  0.518  0.695  1.0
  H  H12  1  0.518  0.482  0.195  1.0
  H  H13  1  0.482  0.518  0.805  1.0
  H  H14  1  0.668  0.332  0.387  1.0
  H  H15  1  0.332  0.668  0.613  1.0
  H  H16  1  0.668  0.332  0.113  1.0
  H  H17  1  0.332  0.668  0.887  1.0
  O  O18  1  0.154  0.846  0.250  1.0
  O  O19  1  0.846  0.154  0.750  1.0
  O  O20  1  0.561  0.906  0.366  1.0
  O  O21  1  0.906  0.561  0.634  1.0
  O  O22  1  0.561  0.906  0.134  1.0
  O  O23  1  0.906  0.561  0.866  1.0
  O  O24  1  0.439  0.094  0.634  1.0
  O  O25  1  0.094  0.439  0.366  1.0
  O  O26  1  0.439  0.094  0.866  1.0
  O  O27  1  0.094  0.439  0.134  1.0
  O  O28  1  0.146  0.854  0.446  1.0
  O  O29  1  0.854  0.146  0.554  1.0
  O  O30  1  0.146  0.854  0.054  1.0
  O  O31  1  0.854  0.146  0.946  1.0
  O  O32  1  0.647  0.353  0.455  1.0
  O  O33  1  0.353  0.647  0.545  1.0
  O  O34  1  0.647  0.353  0.045  1.0
  O  O35  1  0.353  0.647  0.955  1.0
  O  O36  1  0.577  0.423  0.250  1.0
  O  O37  1  0.423  0.577  0.750  1.0
[/CIF]
.
The material described by CaAl2Si2O7(OH)2H2O crystallizes in the orthorhombic Cmcm space group. The structure consists of four water molecules inside a CaAl2Si2O7(OH)2 framework. In the CaAl2Si2O7(OH)2 framework, Ca(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted CaO5 trigonal bipyramids that share corners with four equivalent Al(1)O6 octahedra and corners with six equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. Al(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with two equivalent Ca(1)O5 trigonal bipyramids, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with three equivalent Ca(1)O5 trigonal bipyramids, and edges with two equivalent Al(1)O6 octahedra. H(2) is bonded in a single-bond geometry to one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ca(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Al(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Al(1) and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Al(1) and one H(2) atom. is represented by the CIF file [CIF]
data_CaAl2Si2(H2O5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.804
_cell_length_b   5.804
_cell_length_c   14.066
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   118.788
_symmetry_Int_Tables_number   1
_cell_volume   415.284
_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
  Ca  Ca0  1  0.897  0.103  0.250  1.0
  Ca  Ca1  1  0.103  0.897  0.750  1.0
  Al  Al2  1  0.500  0.000  0.500  1.0
  Al  Al3  1  0.000  0.500  0.500  1.0
  Al  Al4  1  0.500  0.000  0.000  1.0
  Al  Al5  1  0.000  0.500  0.000  1.0
  Si  Si6  1  0.243  0.757  0.350  1.0
  Si  Si7  1  0.757  0.243  0.650  1.0
  Si  Si8  1  0.243  0.757  0.150  1.0
  Si  Si9  1  0.757  0.243  0.850  1.0
  H  H10  1  0.518  0.482  0.305  1.0
  H  H11  1  0.482  0.518  0.695  1.0
  H  H12  1  0.518  0.482  0.195  1.0
  H  H13  1  0.482  0.518  0.805  1.0
  H  H14  1  0.668  0.332  0.387  1.0
  H  H15  1  0.332  0.668  0.613  1.0
  H  H16  1  0.668  0.332  0.113  1.0
  H  H17  1  0.332  0.668  0.887  1.0
  O  O18  1  0.154  0.846  0.250  1.0
  O  O19  1  0.846  0.154  0.750  1.0
  O  O20  1  0.561  0.906  0.366  1.0
  O  O21  1  0.906  0.561  0.634  1.0
  O  O22  1  0.561  0.906  0.134  1.0
  O  O23  1  0.906  0.561  0.866  1.0
  O  O24  1  0.439  0.094  0.634  1.0
  O  O25  1  0.094  0.439  0.366  1.0
  O  O26  1  0.439  0.094  0.866  1.0
  O  O27  1  0.094  0.439  0.134  1.0
  O  O28  1  0.146  0.854  0.446  1.0
  O  O29  1  0.854  0.146  0.554  1.0
  O  O30  1  0.146  0.854  0.054  1.0
  O  O31  1  0.854  0.146  0.946  1.0
  O  O32  1  0.647  0.353  0.455  1.0
  O  O33  1  0.353  0.647  0.545  1.0
  O  O34  1  0.647  0.353  0.045  1.0
  O  O35  1  0.353  0.647  0.955  1.0
  O  O36  1  0.577  0.423  0.250  1.0
  O  O37  1  0.423  0.577  0.750  1.0
[/CIF]
.