The material structure described by CaTi4O8 crystallizes in the monoclinic Cm space group. Ca(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(6), and two equivalent O(7) atoms. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. In the second Ti site, Ti(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. In the third Ti site, Ti(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 50-53°. In the fourth Ti site, Ti(4) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 50-54°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ti(3) and two equivalent Ti(4) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ti(1) and two equivalent Ti(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Ti(4) and two equivalent Ti(2) atoms. In the fourth O site, O(4) is bonded to one Ca(1), one Ti(2), and two equivalent Ti(1) atoms to form distorted OCaTi3 trigonal pyramids that share corners with two equivalent O(4)CaTi3 trigonal pyramids, edges with two equivalent O(7)Ca2Ti3 square pyramids, and edges with two equivalent O(6)Ca2Ti3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Ti(4) and two equivalent Ti(1) atoms. In the sixth O site, O(6) is bonded to two equivalent Ca(1), one Ti(3), and two equivalent Ti(2) atoms to form distorted OCa2Ti3 trigonal bipyramids that share corners with two equivalent O(7)Ca2Ti3 square pyramids,  an edgeedge with one O(7)Ca2Ti3 square pyramid, edges with two equivalent O(6)Ca2Ti3 trigonal bipyramids, and edges with two equivalent O(4)CaTi3 trigonal pyramids. In the seventh O site, O(7) is bonded to two equivalent Ca(1), one Ti(1), and two equivalent Ti(4) atoms to form OCa2Ti3 square pyramids that share corners with two equivalent O(6)Ca2Ti3 trigonal bipyramids, edges with two equivalent O(7)Ca2Ti3 square pyramids,  an edgeedge with one O(6)Ca2Ti3 trigonal bipyramid, and edges with two equivalent O(4)CaTi3 trigonal pyramids. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Ti(2) and two equivalent Ti(3) atoms. is represented by the CIF file [CIF]
data_CaTi4O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.368
_cell_length_b   7.368
_cell_length_c   9.753
_cell_angle_alpha   49.216
_cell_angle_beta   49.216
_cell_angle_gamma   23.685
_symmetry_Int_Tables_number   1
_cell_volume   158.379
_cell_formula_units_Z   1
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  0.622  0.622  0.855  1.0
  Ti  Ti1  1  0.369  0.369  0.438  1.0
  Ti  Ti2  1  0.859  0.859  0.790  1.0
  Ti  Ti3  1  0.166  0.166  0.158  1.0
  Ti  Ti4  1  0.657  0.657  0.496  1.0
  O  O5  1  0.146  0.146  0.373  1.0
  O  O6  1  0.545  0.545  0.235  1.0
  O  O7  1  0.473  0.473  0.710  1.0
  O  O8  1  0.854  0.854  0.592  1.0
  O  O9  1  0.837  0.837  0.337  1.0
  O  O10  1  0.219  0.219  0.903  1.0
  O  O11  1  0.166  0.166  0.639  1.0
  O  O12  1  0.790  0.790  0.041  1.0
[/CIF]
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The material structure described by CaTi4O8 crystallizes in the monoclinic Cm space group. Ca(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(6), and two equivalent O(7) atoms. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. In the second Ti site, Ti(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. In the third Ti site, Ti(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 50-53°. In the fourth Ti site, Ti(4) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 50-54°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ti(3) and two equivalent Ti(4) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ti(1) and two equivalent Ti(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Ti(4) and two equivalent Ti(2) atoms. In the fourth O site, O(4) is bonded to one Ca(1), one Ti(2), and two equivalent Ti(1) atoms to form distorted OCaTi3 trigonal pyramids that share corners with two equivalent O(4)CaTi3 trigonal pyramids, edges with two equivalent O(7)Ca2Ti3 square pyramids, and edges with two equivalent O(6)Ca2Ti3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Ti(4) and two equivalent Ti(1) atoms. In the sixth O site, O(6) is bonded to two equivalent Ca(1), one Ti(3), and two equivalent Ti(2) atoms to form distorted OCa2Ti3 trigonal bipyramids that share corners with two equivalent O(7)Ca2Ti3 square pyramids,  an edgeedge with one O(7)Ca2Ti3 square pyramid, edges with two equivalent O(6)Ca2Ti3 trigonal bipyramids, and edges with two equivalent O(4)CaTi3 trigonal pyramids. In the seventh O site, O(7) is bonded to two equivalent Ca(1), one Ti(1), and two equivalent Ti(4) atoms to form OCa2Ti3 square pyramids that share corners with two equivalent O(6)Ca2Ti3 trigonal bipyramids, edges with two equivalent O(7)Ca2Ti3 square pyramids,  an edgeedge with one O(6)Ca2Ti3 trigonal bipyramid, and edges with two equivalent O(4)CaTi3 trigonal pyramids. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Ti(2) and two equivalent Ti(3) atoms. is represented by the CIF file [CIF]
data_CaTi4O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.368
_cell_length_b   7.368
_cell_length_c   9.753
_cell_angle_alpha   49.216
_cell_angle_beta   49.216
_cell_angle_gamma   23.685
_symmetry_Int_Tables_number   1
_cell_volume   158.379
_cell_formula_units_Z   1
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  0.622  0.622  0.855  1.0
  Ti  Ti1  1  0.369  0.369  0.438  1.0
  Ti  Ti2  1  0.859  0.859  0.790  1.0
  Ti  Ti3  1  0.166  0.166  0.158  1.0
  Ti  Ti4  1  0.657  0.657  0.496  1.0
  O  O5  1  0.146  0.146  0.373  1.0
  O  O6  1  0.545  0.545  0.235  1.0
  O  O7  1  0.473  0.473  0.710  1.0
  O  O8  1  0.854  0.854  0.592  1.0
  O  O9  1  0.837  0.837  0.337  1.0
  O  O10  1  0.219  0.219  0.903  1.0
  O  O11  1  0.166  0.166  0.639  1.0
  O  O12  1  0.790  0.790  0.041  1.0
[/CIF]
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