The material described by CaTi2O4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form distorted CaO6 pentagonal pyramids that share corners with six equivalent Ti(1)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form TiO6 octahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids, edges with two equivalent Ti(1)O6 octahedra, edges with four equivalent Ti(2)O6 octahedra, and  an edgeedge with one Ca(1)O6 pentagonal pyramid. In the second Ti site, Ti(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TiO6 octahedra that share edges with two equivalent Ti(2)O6 octahedra, edges with four equivalent Ti(1)O6 octahedra, and edges with two equivalent Ca(1)O6 pentagonal pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Ti(1), and two equivalent Ti(2) atoms. In the second O site, O(2) is bonded to one Ca(2), one Ti(1), and two equivalent Ti(2) atoms to form OCaTi3 trigonal pyramids that share corners with four equivalent O(3)Ca2Ti3 trigonal bipyramids, corners with three equivalent O(2)CaTi3 trigonal pyramids, and edges with four equivalent O(3)Ca2Ti3 trigonal bipyramids. In the third O site, O(3) is bonded to one Ca(1), one Ca(2), one Ti(2), and two equivalent Ti(1) atoms to form OCa2Ti3 trigonal bipyramids that share corners with five equivalent O(3)Ca2Ti3 trigonal bipyramids, corners with two equivalent O(2)CaTi3 trigonal pyramids, edges with four equivalent O(3)Ca2Ti3 trigonal bipyramids, and edges with two equivalent O(2)CaTi3 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaTi2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.132
_cell_length_b   5.911
_cell_length_c   11.372
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   344.972
_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
  Ca  Ca0  1  0.840  0.000  0.500  1.0
  Ca  Ca1  1  0.160  0.500  0.000  1.0
  Ca  Ca2  1  0.539  0.000  0.000  1.0
  Ca  Ca3  1  0.461  0.500  0.500  1.0
  Ti  Ti4  1  0.527  0.500  0.239  1.0
  Ti  Ti5  1  0.527  0.500  0.761  1.0
  Ti  Ti6  1  0.473  0.000  0.261  1.0
  Ti  Ti7  1  0.473  0.000  0.739  1.0
  Ti  Ti8  1  0.000  0.250  0.250  1.0
  Ti  Ti9  1  0.000  0.750  0.750  1.0
  Ti  Ti10  1  0.000  0.750  0.250  1.0
  Ti  Ti11  1  0.000  0.250  0.750  1.0
  O  O12  1  0.845  0.500  0.142  1.0
  O  O13  1  0.845  0.500  0.858  1.0
  O  O14  1  0.155  0.000  0.358  1.0
  O  O15  1  0.155  0.000  0.642  1.0
  O  O16  1  0.174  0.500  0.340  1.0
  O  O17  1  0.174  0.500  0.660  1.0
  O  O18  1  0.826  0.000  0.160  1.0
  O  O19  1  0.826  0.000  0.840  1.0
  O  O20  1  0.661  0.253  0.356  1.0
  O  O21  1  0.661  0.747  0.644  1.0
  O  O22  1  0.339  0.753  0.144  1.0
  O  O23  1  0.339  0.247  0.856  1.0
  O  O24  1  0.339  0.247  0.144  1.0
  O  O25  1  0.339  0.753  0.856  1.0
  O  O26  1  0.661  0.747  0.356  1.0
  O  O27  1  0.661  0.253  0.644  1.0
[/CIF]
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The material described by CaTi2O4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form distorted CaO6 pentagonal pyramids that share corners with six equivalent Ti(1)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form TiO6 octahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids, edges with two equivalent Ti(1)O6 octahedra, edges with four equivalent Ti(2)O6 octahedra, and  an edgeedge with one Ca(1)O6 pentagonal pyramid. In the second Ti site, Ti(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TiO6 octahedra that share edges with two equivalent Ti(2)O6 octahedra, edges with four equivalent Ti(1)O6 octahedra, and edges with two equivalent Ca(1)O6 pentagonal pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Ti(1), and two equivalent Ti(2) atoms. In the second O site, O(2) is bonded to one Ca(2), one Ti(1), and two equivalent Ti(2) atoms to form OCaTi3 trigonal pyramids that share corners with four equivalent O(3)Ca2Ti3 trigonal bipyramids, corners with three equivalent O(2)CaTi3 trigonal pyramids, and edges with four equivalent O(3)Ca2Ti3 trigonal bipyramids. In the third O site, O(3) is bonded to one Ca(1), one Ca(2), one Ti(2), and two equivalent Ti(1) atoms to form OCa2Ti3 trigonal bipyramids that share corners with five equivalent O(3)Ca2Ti3 trigonal bipyramids, corners with two equivalent O(2)CaTi3 trigonal pyramids, edges with four equivalent O(3)Ca2Ti3 trigonal bipyramids, and edges with two equivalent O(2)CaTi3 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaTi2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.132
_cell_length_b   5.911
_cell_length_c   11.372
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   344.972
_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
  Ca  Ca0  1  0.840  0.000  0.500  1.0
  Ca  Ca1  1  0.160  0.500  0.000  1.0
  Ca  Ca2  1  0.539  0.000  0.000  1.0
  Ca  Ca3  1  0.461  0.500  0.500  1.0
  Ti  Ti4  1  0.527  0.500  0.239  1.0
  Ti  Ti5  1  0.527  0.500  0.761  1.0
  Ti  Ti6  1  0.473  0.000  0.261  1.0
  Ti  Ti7  1  0.473  0.000  0.739  1.0
  Ti  Ti8  1  0.000  0.250  0.250  1.0
  Ti  Ti9  1  0.000  0.750  0.750  1.0
  Ti  Ti10  1  0.000  0.750  0.250  1.0
  Ti  Ti11  1  0.000  0.250  0.750  1.0
  O  O12  1  0.845  0.500  0.142  1.0
  O  O13  1  0.845  0.500  0.858  1.0
  O  O14  1  0.155  0.000  0.358  1.0
  O  O15  1  0.155  0.000  0.642  1.0
  O  O16  1  0.174  0.500  0.340  1.0
  O  O17  1  0.174  0.500  0.660  1.0
  O  O18  1  0.826  0.000  0.160  1.0
  O  O19  1  0.826  0.000  0.840  1.0
  O  O20  1  0.661  0.253  0.356  1.0
  O  O21  1  0.661  0.747  0.644  1.0
  O  O22  1  0.339  0.753  0.144  1.0
  O  O23  1  0.339  0.247  0.856  1.0
  O  O24  1  0.339  0.247  0.144  1.0
  O  O25  1  0.339  0.753  0.856  1.0
  O  O26  1  0.661  0.747  0.356  1.0
  O  O27  1  0.661  0.253  0.644  1.0
[/CIF]
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