The crystal structure described by CaTb2O4 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. Tb(1) is bonded to one O(3), two equivalent O(1), and three equivalent O(2) atoms to form a mixture of corner and edge-sharing TbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted square co-planar geometry to two equivalent Ca(1) and four equivalent Tb(1) atoms. In the second O site, O(2) is bonded to two equivalent Ca(1) and three equivalent Tb(1) atoms to form distorted OCa2Tb3 trigonal bipyramids that share corners with five equivalent O(3)Ca2Tb2 tetrahedra, corners with two equivalent O(2)Ca2Tb3 trigonal bipyramids,  an edgeedge with one O(3)Ca2Tb2 tetrahedra, and edges with five equivalent O(2)Ca2Tb3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ca(1) and two equivalent Tb(1) atoms to form OCa2Tb2 tetrahedra that share corners with two equivalent O(3)Ca2Tb2 tetrahedra, corners with ten equivalent O(2)Ca2Tb3 trigonal bipyramids, and edges with two equivalent O(2)Ca2Tb3 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaTb2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.813
_cell_length_b   5.813
_cell_length_c   11.035
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   146.571
_symmetry_Int_Tables_number   1
_cell_volume   205.423
_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  0.890  0.110  0.250  1.0
  Ca  Ca1  1  0.110  0.890  0.750  1.0
  Tb  Tb2  1  0.633  0.367  0.425  1.0
  Tb  Tb3  1  0.633  0.367  0.075  1.0
  Tb  Tb4  1  0.367  0.633  0.575  1.0
  Tb  Tb5  1  0.367  0.633  0.925  1.0
  O  O6  1  0.000  0.000  0.000  1.0
  O  O7  1  0.000  0.000  0.500  1.0
  O  O8  1  0.734  0.266  0.613  1.0
  O  O9  1  0.532  0.468  0.250  1.0
  O  O10  1  0.468  0.532  0.750  1.0
  O  O11  1  0.266  0.734  0.387  1.0
  O  O12  1  0.734  0.266  0.887  1.0
  O  O13  1  0.266  0.734  0.113  1.0
[/CIF]
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The crystal structure described by CaTb2O4 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. Tb(1) is bonded to one O(3), two equivalent O(1), and three equivalent O(2) atoms to form a mixture of corner and edge-sharing TbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted square co-planar geometry to two equivalent Ca(1) and four equivalent Tb(1) atoms. In the second O site, O(2) is bonded to two equivalent Ca(1) and three equivalent Tb(1) atoms to form distorted OCa2Tb3 trigonal bipyramids that share corners with five equivalent O(3)Ca2Tb2 tetrahedra, corners with two equivalent O(2)Ca2Tb3 trigonal bipyramids,  an edgeedge with one O(3)Ca2Tb2 tetrahedra, and edges with five equivalent O(2)Ca2Tb3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ca(1) and two equivalent Tb(1) atoms to form OCa2Tb2 tetrahedra that share corners with two equivalent O(3)Ca2Tb2 tetrahedra, corners with ten equivalent O(2)Ca2Tb3 trigonal bipyramids, and edges with two equivalent O(2)Ca2Tb3 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaTb2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.813
_cell_length_b   5.813
_cell_length_c   11.035
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   146.571
_symmetry_Int_Tables_number   1
_cell_volume   205.423
_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  0.890  0.110  0.250  1.0
  Ca  Ca1  1  0.110  0.890  0.750  1.0
  Tb  Tb2  1  0.633  0.367  0.425  1.0
  Tb  Tb3  1  0.633  0.367  0.075  1.0
  Tb  Tb4  1  0.367  0.633  0.575  1.0
  Tb  Tb5  1  0.367  0.633  0.925  1.0
  O  O6  1  0.000  0.000  0.000  1.0
  O  O7  1  0.000  0.000  0.500  1.0
  O  O8  1  0.734  0.266  0.613  1.0
  O  O9  1  0.532  0.468  0.250  1.0
  O  O10  1  0.468  0.532  0.750  1.0
  O  O11  1  0.266  0.734  0.387  1.0
  O  O12  1  0.734  0.266  0.887  1.0
  O  O13  1  0.266  0.734  0.113  1.0
[/CIF]
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