The material described by CaH2 is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded in a 9-coordinate geometry to four equivalent H(2) and five equivalent H(1) atoms. There are two inequivalent H sites. In the first H site, H(2) is bonded to four equivalent Ca(1) atoms to form HCa4 tetrahedra that share corners with eight equivalent H(1)Ca5 square pyramids, corners with eight equivalent H(2)Ca4 tetrahedra, edges with six equivalent H(1)Ca5 square pyramids, and edges with two equivalent H(2)Ca4 tetrahedra. In the second H site, H(1) is bonded to five equivalent Ca(1) atoms to form distorted HCa5 square pyramids that share corners with eight equivalent H(1)Ca5 square pyramids, corners with eight equivalent H(2)Ca4 tetrahedra, edges with six equivalent H(1)Ca5 square pyramids, and edges with six equivalent H(2)Ca4 tetrahedra. is represented by the CIF card [CIF]
data_CaH2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.568
_cell_length_b   5.899
_cell_length_c   6.775
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   142.596
_cell_formula_units_Z   4
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  0.250  0.739  0.389  1.0
  Ca  Ca1  1  0.750  0.261  0.611  1.0
  Ca  Ca2  1  0.250  0.239  0.111  1.0
  Ca  Ca3  1  0.750  0.761  0.889  1.0
  H  H4  1  0.250  0.474  0.823  1.0
  H  H5  1  0.750  0.526  0.177  1.0
  H  H6  1  0.250  0.974  0.677  1.0
  H  H7  1  0.750  0.026  0.323  1.0
  H  H8  1  0.750  0.645  0.572  1.0
  H  H9  1  0.250  0.355  0.428  1.0
  H  H10  1  0.750  0.145  0.928  1.0
  H  H11  1  0.250  0.855  0.072  1.0
[/CIF]
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The material described by CaH2 is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded in a 9-coordinate geometry to four equivalent H(2) and five equivalent H(1) atoms. There are two inequivalent H sites. In the first H site, H(2) is bonded to four equivalent Ca(1) atoms to form HCa4 tetrahedra that share corners with eight equivalent H(1)Ca5 square pyramids, corners with eight equivalent H(2)Ca4 tetrahedra, edges with six equivalent H(1)Ca5 square pyramids, and edges with two equivalent H(2)Ca4 tetrahedra. In the second H site, H(1) is bonded to five equivalent Ca(1) atoms to form distorted HCa5 square pyramids that share corners with eight equivalent H(1)Ca5 square pyramids, corners with eight equivalent H(2)Ca4 tetrahedra, edges with six equivalent H(1)Ca5 square pyramids, and edges with six equivalent H(2)Ca4 tetrahedra. is represented by the CIF card [CIF]
data_CaH2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.568
_cell_length_b   5.899
_cell_length_c   6.775
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   142.596
_cell_formula_units_Z   4
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  0.250  0.739  0.389  1.0
  Ca  Ca1  1  0.750  0.261  0.611  1.0
  Ca  Ca2  1  0.250  0.239  0.111  1.0
  Ca  Ca3  1  0.750  0.761  0.889  1.0
  H  H4  1  0.250  0.474  0.823  1.0
  H  H5  1  0.750  0.526  0.177  1.0
  H  H6  1  0.250  0.974  0.677  1.0
  H  H7  1  0.750  0.026  0.323  1.0
  H  H8  1  0.750  0.645  0.572  1.0
  H  H9  1  0.250  0.355  0.428  1.0
  H  H10  1  0.750  0.145  0.928  1.0
  H  H11  1  0.250  0.855  0.072  1.0
[/CIF]
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