The crystal structure described by NaCaH3 crystallizes in the triclinic P-1 space group. Na(1) is bonded to one H(2), two equivalent H(1), and two equivalent H(3) atoms to form a mixture of distorted edge and corner-sharing NaH5 square pyramids. Ca(1) is bonded in a 7-coordinate geometry to two equivalent H(1), two equivalent H(3), and three equivalent H(2) atoms. There are three inequivalent H sites. In the first H site, H(1) is bonded to two equivalent Na(1) and two equivalent Ca(1) atoms to form HNa2Ca2 tetrahedra that share corners with two equivalent H(1)Na2Ca2 tetrahedra, corners with four equivalent H(3)Na2Ca2 tetrahedra, corners with eight equivalent H(2)NaCa3 trigonal pyramids,  an edgeedge with one H(1)Na2Ca2 tetrahedra, and edges with two equivalent H(3)Na2Ca2 tetrahedra. In the second H site, H(2) is bonded to one Na(1) and three equivalent Ca(1) atoms to form HNaCa3 trigonal pyramids that share corners with four equivalent H(3)Na2Ca2 tetrahedra, corners with eight equivalent H(1)Na2Ca2 tetrahedra, corners with two equivalent H(2)NaCa3 trigonal pyramids, edges with two equivalent H(3)Na2Ca2 tetrahedra, and edges with two equivalent H(2)NaCa3 trigonal pyramids. In the third H site, H(3) is bonded to two equivalent Na(1) and two equivalent Ca(1) atoms to form HNa2Ca2 tetrahedra that share corners with two equivalent H(3)Na2Ca2 tetrahedra, corners with four equivalent H(1)Na2Ca2 tetrahedra, corners with four equivalent H(2)NaCa3 trigonal pyramids,  an edgeedge with one H(3)Na2Ca2 tetrahedra, edges with two equivalent H(1)Na2Ca2 tetrahedra, and edges with two equivalent H(2)NaCa3 trigonal pyramids. is represented by the CIF file [CIF]
data_NaCaH3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.631
_cell_length_b   6.814
_cell_length_c   6.866
_cell_angle_alpha   117.010
_cell_angle_beta   99.712
_cell_angle_gamma   95.211
_symmetry_Int_Tables_number   1
_cell_volume   146.432
_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
  Na  Na0  1  0.987  0.726  0.261  1.0
  Na  Na1  1  0.013  0.274  0.739  1.0
  Ca  Ca2  1  0.371  0.248  0.210  1.0
  Ca  Ca3  1  0.629  0.752  0.790  1.0
  H  H4  1  0.483  0.350  0.582  1.0
  H  H5  1  0.517  0.650  0.418  1.0
  H  H6  1  0.178  0.985  0.815  1.0
  H  H7  1  0.822  0.015  0.185  1.0
  H  H8  1  0.160  0.653  0.927  1.0
  H  H9  1  0.840  0.347  0.073  1.0
[/CIF]
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The crystal structure described by NaCaH3 crystallizes in the triclinic P-1 space group. Na(1) is bonded to one H(2), two equivalent H(1), and two equivalent H(3) atoms to form a mixture of distorted edge and corner-sharing NaH5 square pyramids. Ca(1) is bonded in a 7-coordinate geometry to two equivalent H(1), two equivalent H(3), and three equivalent H(2) atoms. There are three inequivalent H sites. In the first H site, H(1) is bonded to two equivalent Na(1) and two equivalent Ca(1) atoms to form HNa2Ca2 tetrahedra that share corners with two equivalent H(1)Na2Ca2 tetrahedra, corners with four equivalent H(3)Na2Ca2 tetrahedra, corners with eight equivalent H(2)NaCa3 trigonal pyramids,  an edgeedge with one H(1)Na2Ca2 tetrahedra, and edges with two equivalent H(3)Na2Ca2 tetrahedra. In the second H site, H(2) is bonded to one Na(1) and three equivalent Ca(1) atoms to form HNaCa3 trigonal pyramids that share corners with four equivalent H(3)Na2Ca2 tetrahedra, corners with eight equivalent H(1)Na2Ca2 tetrahedra, corners with two equivalent H(2)NaCa3 trigonal pyramids, edges with two equivalent H(3)Na2Ca2 tetrahedra, and edges with two equivalent H(2)NaCa3 trigonal pyramids. In the third H site, H(3) is bonded to two equivalent Na(1) and two equivalent Ca(1) atoms to form HNa2Ca2 tetrahedra that share corners with two equivalent H(3)Na2Ca2 tetrahedra, corners with four equivalent H(1)Na2Ca2 tetrahedra, corners with four equivalent H(2)NaCa3 trigonal pyramids,  an edgeedge with one H(3)Na2Ca2 tetrahedra, edges with two equivalent H(1)Na2Ca2 tetrahedra, and edges with two equivalent H(2)NaCa3 trigonal pyramids. is represented by the CIF file [CIF]
data_NaCaH3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.631
_cell_length_b   6.814
_cell_length_c   6.866
_cell_angle_alpha   117.010
_cell_angle_beta   99.712
_cell_angle_gamma   95.211
_symmetry_Int_Tables_number   1
_cell_volume   146.432
_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
  Na  Na0  1  0.987  0.726  0.261  1.0
  Na  Na1  1  0.013  0.274  0.739  1.0
  Ca  Ca2  1  0.371  0.248  0.210  1.0
  Ca  Ca3  1  0.629  0.752  0.790  1.0
  H  H4  1  0.483  0.350  0.582  1.0
  H  H5  1  0.517  0.650  0.418  1.0
  H  H6  1  0.178  0.985  0.815  1.0
  H  H7  1  0.822  0.015  0.185  1.0
  H  H8  1  0.160  0.653  0.927  1.0
  H  H9  1  0.840  0.347  0.073  1.0
[/CIF]
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