The material described by CaH2 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 11-coordinate geometry to five equivalent H(1) and six equivalent H(2) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded to five equivalent Ca(1) atoms to form distorted HCa5 trigonal bipyramids that share corners with twelve equivalent H(2)Ca6 octahedra, corners with eight equivalent H(1)Ca5 trigonal bipyramids, edges with six equivalent H(1)Ca5 trigonal bipyramids, and faces with six equivalent H(2)Ca6 octahedra. The corner-sharing octahedral tilt angles range from 31-60°. In the second H site, H(2) is bonded to six equivalent Ca(1) atoms to form HCa6 octahedra that share corners with twelve equivalent H(2)Ca6 octahedra, corners with twelve equivalent H(1)Ca5 trigonal bipyramids, edges with six equivalent H(2)Ca6 octahedra, faces with two equivalent H(2)Ca6 octahedra, and faces with six equivalent H(1)Ca5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 50-51°. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaH2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.828
_cell_length_b   3.828
_cell_length_c   5.346
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.828
_symmetry_Int_Tables_number   1
_cell_volume   67.256
_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  0.162  0.838  0.250  1.0
  Ca  Ca1  1  0.838  0.162  0.750  1.0
  H  H2  1  0.831  0.169  0.250  1.0
  H  H3  1  0.169  0.831  0.750  1.0
  H  H4  1  0.500  0.500  0.000  1.0
  H  H5  1  0.500  0.500  0.500  1.0
[/CIF]
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The material described by CaH2 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 11-coordinate geometry to five equivalent H(1) and six equivalent H(2) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded to five equivalent Ca(1) atoms to form distorted HCa5 trigonal bipyramids that share corners with twelve equivalent H(2)Ca6 octahedra, corners with eight equivalent H(1)Ca5 trigonal bipyramids, edges with six equivalent H(1)Ca5 trigonal bipyramids, and faces with six equivalent H(2)Ca6 octahedra. The corner-sharing octahedral tilt angles range from 31-60°. In the second H site, H(2) is bonded to six equivalent Ca(1) atoms to form HCa6 octahedra that share corners with twelve equivalent H(2)Ca6 octahedra, corners with twelve equivalent H(1)Ca5 trigonal bipyramids, edges with six equivalent H(2)Ca6 octahedra, faces with two equivalent H(2)Ca6 octahedra, and faces with six equivalent H(1)Ca5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 50-51°. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaH2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.828
_cell_length_b   3.828
_cell_length_c   5.346
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.828
_symmetry_Int_Tables_number   1
_cell_volume   67.256
_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  0.162  0.838  0.250  1.0
  Ca  Ca1  1  0.838  0.162  0.750  1.0
  H  H2  1  0.831  0.169  0.250  1.0
  H  H3  1  0.169  0.831  0.750  1.0
  H  H4  1  0.500  0.500  0.000  1.0
  H  H5  1  0.500  0.500  0.500  1.0
[/CIF]
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