The material structure described by MgCe(NiH)4 crystallizes in the orthorhombic Pmn2_1 space group. Mg(1) is bonded in a 3-coordinate geometry to one H(1) and two equivalent H(3) atoms. Ce(1) is bonded in a 7-coordinate geometry to one H(2), two equivalent H(1), and four equivalent H(3) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a water-like geometry to one H(1) and one H(2) atom. In the second Ni site, Ni(2) is bonded in a distorted trigonal non-coplanar geometry to one H(1) and two equivalent H(3) atoms. In the third Ni site, Ni(3) is bonded in a distorted water-like geometry to one H(2) and one H(3) atom. There are three inequivalent H sites. In the first H site, H(1) is bonded to one Mg(1), two equivalent Ce(1), one Ni(1), and one Ni(2) atom to form distorted HCe2MgNi2 trigonal bipyramids that share corners with three equivalent H(2)CeNi3 tetrahedra, corners with two equivalent H(1)Ce2MgNi2 trigonal bipyramids, corners with four equivalent H(3)Ce2MgNi2 trigonal bipyramids, and edges with four equivalent H(3)Ce2MgNi2 trigonal bipyramids. In the second H site, H(2) is bonded to one Ce(1), one Ni(1), and two equivalent Ni(3) atoms to form corner-sharing HCeNi3 tetrahedra. In the third H site, H(3) is bonded to one Mg(1), two equivalent Ce(1), one Ni(2), and one Ni(3) atom to form distorted HCe2MgNi2 trigonal bipyramids that share corners with three equivalent H(2)CeNi3 tetrahedra, corners with two equivalent H(1)Ce2MgNi2 trigonal bipyramids, corners with four equivalent H(3)Ce2MgNi2 trigonal bipyramids, edges with two equivalent H(1)Ce2MgNi2 trigonal bipyramids, and edges with two equivalent H(3)Ce2MgNi2 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_CeMg(NiH)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.004
_cell_length_b   5.431
_cell_length_c   7.317
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   198.828
_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
  Ce  Ce0  1  0.000  0.698  0.489  1.0
  Ce  Ce1  1  0.500  0.302  0.989  1.0
  Mg  Mg2  1  0.000  0.184  0.711  1.0
  Mg  Mg3  1  0.500  0.816  0.211  1.0
  Ni  Ni4  1  0.000  0.011  0.091  1.0
  Ni  Ni5  1  0.500  0.989  0.591  1.0
  Ni  Ni6  1  0.000  0.550  0.113  1.0
  Ni  Ni7  1  0.500  0.450  0.613  1.0
  Ni  Ni8  1  0.254  0.229  0.366  1.0
  Ni  Ni9  1  0.246  0.771  0.866  1.0
  Ni  Ni10  1  0.754  0.771  0.866  1.0
  Ni  Ni11  1  0.746  0.229  0.366  1.0
  H  H12  1  0.000  0.281  0.996  1.0
  H  H13  1  0.500  0.719  0.496  1.0
  H  H14  1  0.000  0.054  0.313  1.0
  H  H15  1  0.500  0.946  0.813  1.0
  H  H16  1  0.257  0.491  0.243  1.0
  H  H17  1  0.243  0.509  0.743  1.0
  H  H18  1  0.757  0.509  0.743  1.0
  H  H19  1  0.743  0.491  0.243  1.0
[/CIF]
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The material structure described by MgCe(NiH)4 crystallizes in the orthorhombic Pmn2_1 space group. Mg(1) is bonded in a 3-coordinate geometry to one H(1) and two equivalent H(3) atoms. Ce(1) is bonded in a 7-coordinate geometry to one H(2), two equivalent H(1), and four equivalent H(3) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a water-like geometry to one H(1) and one H(2) atom. In the second Ni site, Ni(2) is bonded in a distorted trigonal non-coplanar geometry to one H(1) and two equivalent H(3) atoms. In the third Ni site, Ni(3) is bonded in a distorted water-like geometry to one H(2) and one H(3) atom. There are three inequivalent H sites. In the first H site, H(1) is bonded to one Mg(1), two equivalent Ce(1), one Ni(1), and one Ni(2) atom to form distorted HCe2MgNi2 trigonal bipyramids that share corners with three equivalent H(2)CeNi3 tetrahedra, corners with two equivalent H(1)Ce2MgNi2 trigonal bipyramids, corners with four equivalent H(3)Ce2MgNi2 trigonal bipyramids, and edges with four equivalent H(3)Ce2MgNi2 trigonal bipyramids. In the second H site, H(2) is bonded to one Ce(1), one Ni(1), and two equivalent Ni(3) atoms to form corner-sharing HCeNi3 tetrahedra. In the third H site, H(3) is bonded to one Mg(1), two equivalent Ce(1), one Ni(2), and one Ni(3) atom to form distorted HCe2MgNi2 trigonal bipyramids that share corners with three equivalent H(2)CeNi3 tetrahedra, corners with two equivalent H(1)Ce2MgNi2 trigonal bipyramids, corners with four equivalent H(3)Ce2MgNi2 trigonal bipyramids, edges with two equivalent H(1)Ce2MgNi2 trigonal bipyramids, and edges with two equivalent H(3)Ce2MgNi2 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_CeMg(NiH)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.004
_cell_length_b   5.431
_cell_length_c   7.317
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   198.828
_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
  Ce  Ce0  1  0.000  0.698  0.489  1.0
  Ce  Ce1  1  0.500  0.302  0.989  1.0
  Mg  Mg2  1  0.000  0.184  0.711  1.0
  Mg  Mg3  1  0.500  0.816  0.211  1.0
  Ni  Ni4  1  0.000  0.011  0.091  1.0
  Ni  Ni5  1  0.500  0.989  0.591  1.0
  Ni  Ni6  1  0.000  0.550  0.113  1.0
  Ni  Ni7  1  0.500  0.450  0.613  1.0
  Ni  Ni8  1  0.254  0.229  0.366  1.0
  Ni  Ni9  1  0.246  0.771  0.866  1.0
  Ni  Ni10  1  0.754  0.771  0.866  1.0
  Ni  Ni11  1  0.746  0.229  0.366  1.0
  H  H12  1  0.000  0.281  0.996  1.0
  H  H13  1  0.500  0.719  0.496  1.0
  H  H14  1  0.000  0.054  0.313  1.0
  H  H15  1  0.500  0.946  0.813  1.0
  H  H16  1  0.257  0.491  0.243  1.0
  H  H17  1  0.243  0.509  0.743  1.0
  H  H18  1  0.757  0.509  0.743  1.0
  H  H19  1  0.743  0.491  0.243  1.0
[/CIF]
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