The crystal structure described by Mg2NiH4 crystallizes in the monoclinic C2/c space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to two equivalent H(2), two equivalent H(4), and three equivalent H(1) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent H(3) and two equivalent H(4) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to two equivalent H(2) and four equivalent H(3) atoms. Ni(1) is bonded in a tetrahedral geometry to one H(1), one H(2), one H(3), and one H(4) atom. There are four inequivalent H sites. In the first H site, H(3) is bonded in a distorted see-saw-like geometry to one Mg(2), two equivalent Mg(3), and one Ni(1) atom. In the second H site, H(4) is bonded in a 4-coordinate geometry to one Mg(2), two equivalent Mg(1), and one Ni(1) atom. In the third H site, H(1) is bonded in a distorted see-saw-like geometry to three equivalent Mg(1) and one Ni(1) atom. In the fourth H site, H(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(3), two equivalent Mg(1), and one Ni(1) atom. is represented by the CIF card [CIF]
data_Mg2NiH4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.787
_cell_length_b   7.787
_cell_length_c   6.420
_cell_angle_alpha   68.793
_cell_angle_beta   68.793
_cell_angle_gamma   48.069
_symmetry_Int_Tables_number   1
_cell_volume   265.922
_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
  Mg  Mg0  1  0.224  0.248  0.080  1.0
  Mg  Mg1  1  0.752  0.776  0.420  1.0
  Mg  Mg2  1  0.776  0.752  0.920  1.0
  Mg  Mg3  1  0.248  0.224  0.580  1.0
  Mg  Mg4  1  0.023  0.977  0.250  1.0
  Mg  Mg5  1  0.977  0.023  0.750  1.0
  Mg  Mg6  1  0.526  0.474  0.250  1.0
  Mg  Mg7  1  0.474  0.526  0.750  1.0
  Ni  Ni8  1  0.110  0.650  0.082  1.0
  Ni  Ni9  1  0.350  0.890  0.418  1.0
  Ni  Ni10  1  0.890  0.350  0.918  1.0
  Ni  Ni11  1  0.650  0.110  0.582  1.0
  H  H12  1  0.099  0.485  0.303  1.0
  H  H13  1  0.515  0.901  0.197  1.0
  H  H14  1  0.901  0.515  0.697  1.0
  H  H15  1  0.485  0.099  0.803  1.0
  H  H16  1  0.177  0.546  0.878  1.0
  H  H17  1  0.454  0.823  0.622  1.0
  H  H18  1  0.823  0.454  0.122  1.0
  H  H19  1  0.546  0.177  0.378  1.0
  H  H20  1  0.280  0.700  0.053  1.0
  H  H21  1  0.300  0.720  0.447  1.0
  H  H22  1  0.720  0.300  0.947  1.0
  H  H23  1  0.700  0.280  0.553  1.0
  H  H24  1  0.865  0.887  0.078  1.0
  H  H25  1  0.113  0.135  0.422  1.0
  H  H26  1  0.135  0.113  0.922  1.0
  H  H27  1  0.887  0.865  0.578  1.0
[/CIF]
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The crystal structure described by Mg2NiH4 crystallizes in the monoclinic C2/c space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to two equivalent H(2), two equivalent H(4), and three equivalent H(1) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent H(3) and two equivalent H(4) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to two equivalent H(2) and four equivalent H(3) atoms. Ni(1) is bonded in a tetrahedral geometry to one H(1), one H(2), one H(3), and one H(4) atom. There are four inequivalent H sites. In the first H site, H(3) is bonded in a distorted see-saw-like geometry to one Mg(2), two equivalent Mg(3), and one Ni(1) atom. In the second H site, H(4) is bonded in a 4-coordinate geometry to one Mg(2), two equivalent Mg(1), and one Ni(1) atom. In the third H site, H(1) is bonded in a distorted see-saw-like geometry to three equivalent Mg(1) and one Ni(1) atom. In the fourth H site, H(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(3), two equivalent Mg(1), and one Ni(1) atom. is represented by the CIF card [CIF]
data_Mg2NiH4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.787
_cell_length_b   7.787
_cell_length_c   6.420
_cell_angle_alpha   68.793
_cell_angle_beta   68.793
_cell_angle_gamma   48.069
_symmetry_Int_Tables_number   1
_cell_volume   265.922
_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
  Mg  Mg0  1  0.224  0.248  0.080  1.0
  Mg  Mg1  1  0.752  0.776  0.420  1.0
  Mg  Mg2  1  0.776  0.752  0.920  1.0
  Mg  Mg3  1  0.248  0.224  0.580  1.0
  Mg  Mg4  1  0.023  0.977  0.250  1.0
  Mg  Mg5  1  0.977  0.023  0.750  1.0
  Mg  Mg6  1  0.526  0.474  0.250  1.0
  Mg  Mg7  1  0.474  0.526  0.750  1.0
  Ni  Ni8  1  0.110  0.650  0.082  1.0
  Ni  Ni9  1  0.350  0.890  0.418  1.0
  Ni  Ni10  1  0.890  0.350  0.918  1.0
  Ni  Ni11  1  0.650  0.110  0.582  1.0
  H  H12  1  0.099  0.485  0.303  1.0
  H  H13  1  0.515  0.901  0.197  1.0
  H  H14  1  0.901  0.515  0.697  1.0
  H  H15  1  0.485  0.099  0.803  1.0
  H  H16  1  0.177  0.546  0.878  1.0
  H  H17  1  0.454  0.823  0.622  1.0
  H  H18  1  0.823  0.454  0.122  1.0
  H  H19  1  0.546  0.177  0.378  1.0
  H  H20  1  0.280  0.700  0.053  1.0
  H  H21  1  0.300  0.720  0.447  1.0
  H  H22  1  0.720  0.300  0.947  1.0
  H  H23  1  0.700  0.280  0.553  1.0
  H  H24  1  0.865  0.887  0.078  1.0
  H  H25  1  0.113  0.135  0.422  1.0
  H  H26  1  0.135  0.113  0.922  1.0
  H  H27  1  0.887  0.865  0.578  1.0
[/CIF]
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