The material structure described by CaZr4O9 crystallizes in the monoclinic C2/m 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(2) atoms to form distorted edge-sharing CaO6 octahedra. In the second Ca site, Ca(2) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(3) atoms. There are four inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a 6-coordinate geometry to one O(2), one O(5), two equivalent O(1), and two equivalent O(4) atoms. In the second Zr site, Zr(2) is bonded in a 7-coordinate geometry to one O(1), one O(4), one O(7), two equivalent O(3), and two equivalent O(5) atoms. In the third Zr site, Zr(3) is bonded in a 8-coordinate geometry to one O(4), one O(7), one O(9), two equivalent O(8), and three equivalent O(6) atoms. In the fourth Zr site, Zr(4) is bonded in a distorted body-centered cubic geometry to one O(5), one O(6), one O(8), two equivalent O(7), and three equivalent O(9) atoms. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Zr(2), and two equivalent Zr(1) atoms to form OCaZr3 tetrahedra that share  a cornercorner with one O(7)Zr4 tetrahedra, corners with two equivalent O(2)Ca3Zr tetrahedra, corners with three equivalent O(1)CaZr3 tetrahedra, edges with two equivalent O(2)Ca3Zr tetrahedra, and edges with two equivalent O(5)Zr4 tetrahedra. In the second O site, O(2) is bonded to one Ca(2), two equivalent Ca(1), and one Zr(1) atom to form OCa3Zr tetrahedra that share  a cornercorner with one O(5)Zr4 tetrahedra, corners with two equivalent O(1)CaZr3 tetrahedra, corners with five equivalent O(2)Ca3Zr tetrahedra,  an edgeedge with one O(2)Ca3Zr tetrahedra, and edges with two equivalent O(1)CaZr3 tetrahedra. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(2) and two equivalent Zr(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Zr(2), one Zr(3), and two equivalent Zr(1) atoms. In the fifth O site, O(5) is bonded to one Zr(1), one Zr(4), and two equivalent Zr(2) atoms to form distorted OZr4 tetrahedra that share  a cornercorner with one O(2)Ca3Zr tetrahedra,  a cornercorner with one O(6)Zr4 tetrahedra, corners with two equivalent O(5)Zr4 tetrahedra, corners with three equivalent O(9)Zr4 tetrahedra, edges with two equivalent O(1)CaZr3 tetrahedra, and edges with two equivalent O(7)Zr4 tetrahedra. In the sixth O site, O(6) is bonded to one Zr(4) and three equivalent Zr(3) atoms to form a mixture of distorted edge and corner-sharing OZr4 tetrahedra. In the seventh O site, O(7) is bonded to one Zr(2), one Zr(3), and two equivalent Zr(4) atoms to form distorted OZr4 tetrahedra that share  a cornercorner with one O(1)CaZr3 tetrahedra,  a cornercorner with one O(6)Zr4 tetrahedra, corners with two equivalent O(7)Zr4 tetrahedra, corners with five equivalent O(9)Zr4 tetrahedra,  an edgeedge with one O(9)Zr4 tetrahedra, edges with two equivalent O(5)Zr4 tetrahedra, and edges with two equivalent O(6)Zr4 tetrahedra. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Zr(4) and two equivalent Zr(3) atoms. In the ninth O site, O(9) is bonded to one Zr(3) and three equivalent Zr(4) atoms to form a mixture of distorted edge and corner-sharing OZr4 tetrahedra. is represented by the CIF file [CIF]
data_CaZr4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   15.782
_cell_length_b   15.782
_cell_length_c   6.503
_cell_angle_alpha   86.556
_cell_angle_beta   86.556
_cell_angle_gamma   12.759
_symmetry_Int_Tables_number   1
_cell_volume   357.014
_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  0.500  0.500  0.000  1.0
  Ca  Ca1  1  0.000  0.000  0.500  1.0
  Zr  Zr2  1  0.093  0.093  0.821  1.0
  Zr  Zr3  1  0.605  0.605  0.297  1.0
  Zr  Zr4  1  0.907  0.907  0.179  1.0
  Zr  Zr5  1  0.703  0.703  0.601  1.0
  Zr  Zr6  1  0.395  0.395  0.703  1.0
  Zr  Zr7  1  0.297  0.297  0.399  1.0
  Zr  Zr8  1  0.200  0.200  0.100  1.0
  Zr  Zr9  1  0.800  0.800  0.900  1.0
  O  O10  1  0.573  0.573  0.029  1.0
  O  O11  1  0.972  0.972  0.204  1.0
  O  O12  1  0.071  0.071  0.393  1.0
  O  O13  1  0.388  0.388  0.350  1.0
  O  O14  1  0.929  0.929  0.607  1.0
  O  O15  1  0.028  0.028  0.796  1.0
  O  O16  1  0.867  0.867  0.912  1.0
  O  O17  1  0.769  0.769  0.618  1.0
  O  O18  1  0.328  0.328  0.681  1.0
  O  O19  1  0.181  0.181  0.734  1.0
  O  O20  1  0.427  0.427  0.971  1.0
  O  O21  1  0.280  0.280  0.039  1.0
  O  O22  1  0.720  0.720  0.961  1.0
  O  O23  1  0.819  0.819  0.266  1.0
  O  O24  1  0.672  0.672  0.319  1.0
  O  O25  1  0.133  0.133  0.088  1.0
  O  O26  1  0.231  0.231  0.382  1.0
  O  O27  1  0.612  0.612  0.650  1.0
[/CIF]
.
The material structure described by CaZr4O9 crystallizes in the monoclinic C2/m 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(2) atoms to form distorted edge-sharing CaO6 octahedra. In the second Ca site, Ca(2) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(3) atoms. There are four inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a 6-coordinate geometry to one O(2), one O(5), two equivalent O(1), and two equivalent O(4) atoms. In the second Zr site, Zr(2) is bonded in a 7-coordinate geometry to one O(1), one O(4), one O(7), two equivalent O(3), and two equivalent O(5) atoms. In the third Zr site, Zr(3) is bonded in a 8-coordinate geometry to one O(4), one O(7), one O(9), two equivalent O(8), and three equivalent O(6) atoms. In the fourth Zr site, Zr(4) is bonded in a distorted body-centered cubic geometry to one O(5), one O(6), one O(8), two equivalent O(7), and three equivalent O(9) atoms. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Zr(2), and two equivalent Zr(1) atoms to form OCaZr3 tetrahedra that share  a cornercorner with one O(7)Zr4 tetrahedra, corners with two equivalent O(2)Ca3Zr tetrahedra, corners with three equivalent O(1)CaZr3 tetrahedra, edges with two equivalent O(2)Ca3Zr tetrahedra, and edges with two equivalent O(5)Zr4 tetrahedra. In the second O site, O(2) is bonded to one Ca(2), two equivalent Ca(1), and one Zr(1) atom to form OCa3Zr tetrahedra that share  a cornercorner with one O(5)Zr4 tetrahedra, corners with two equivalent O(1)CaZr3 tetrahedra, corners with five equivalent O(2)Ca3Zr tetrahedra,  an edgeedge with one O(2)Ca3Zr tetrahedra, and edges with two equivalent O(1)CaZr3 tetrahedra. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(2) and two equivalent Zr(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Zr(2), one Zr(3), and two equivalent Zr(1) atoms. In the fifth O site, O(5) is bonded to one Zr(1), one Zr(4), and two equivalent Zr(2) atoms to form distorted OZr4 tetrahedra that share  a cornercorner with one O(2)Ca3Zr tetrahedra,  a cornercorner with one O(6)Zr4 tetrahedra, corners with two equivalent O(5)Zr4 tetrahedra, corners with three equivalent O(9)Zr4 tetrahedra, edges with two equivalent O(1)CaZr3 tetrahedra, and edges with two equivalent O(7)Zr4 tetrahedra. In the sixth O site, O(6) is bonded to one Zr(4) and three equivalent Zr(3) atoms to form a mixture of distorted edge and corner-sharing OZr4 tetrahedra. In the seventh O site, O(7) is bonded to one Zr(2), one Zr(3), and two equivalent Zr(4) atoms to form distorted OZr4 tetrahedra that share  a cornercorner with one O(1)CaZr3 tetrahedra,  a cornercorner with one O(6)Zr4 tetrahedra, corners with two equivalent O(7)Zr4 tetrahedra, corners with five equivalent O(9)Zr4 tetrahedra,  an edgeedge with one O(9)Zr4 tetrahedra, edges with two equivalent O(5)Zr4 tetrahedra, and edges with two equivalent O(6)Zr4 tetrahedra. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Zr(4) and two equivalent Zr(3) atoms. In the ninth O site, O(9) is bonded to one Zr(3) and three equivalent Zr(4) atoms to form a mixture of distorted edge and corner-sharing OZr4 tetrahedra. is represented by the CIF file [CIF]
data_CaZr4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   15.782
_cell_length_b   15.782
_cell_length_c   6.503
_cell_angle_alpha   86.556
_cell_angle_beta   86.556
_cell_angle_gamma   12.759
_symmetry_Int_Tables_number   1
_cell_volume   357.014
_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  0.500  0.500  0.000  1.0
  Ca  Ca1  1  0.000  0.000  0.500  1.0
  Zr  Zr2  1  0.093  0.093  0.821  1.0
  Zr  Zr3  1  0.605  0.605  0.297  1.0
  Zr  Zr4  1  0.907  0.907  0.179  1.0
  Zr  Zr5  1  0.703  0.703  0.601  1.0
  Zr  Zr6  1  0.395  0.395  0.703  1.0
  Zr  Zr7  1  0.297  0.297  0.399  1.0
  Zr  Zr8  1  0.200  0.200  0.100  1.0
  Zr  Zr9  1  0.800  0.800  0.900  1.0
  O  O10  1  0.573  0.573  0.029  1.0
  O  O11  1  0.972  0.972  0.204  1.0
  O  O12  1  0.071  0.071  0.393  1.0
  O  O13  1  0.388  0.388  0.350  1.0
  O  O14  1  0.929  0.929  0.607  1.0
  O  O15  1  0.028  0.028  0.796  1.0
  O  O16  1  0.867  0.867  0.912  1.0
  O  O17  1  0.769  0.769  0.618  1.0
  O  O18  1  0.328  0.328  0.681  1.0
  O  O19  1  0.181  0.181  0.734  1.0
  O  O20  1  0.427  0.427  0.971  1.0
  O  O21  1  0.280  0.280  0.039  1.0
  O  O22  1  0.720  0.720  0.961  1.0
  O  O23  1  0.819  0.819  0.266  1.0
  O  O24  1  0.672  0.672  0.319  1.0
  O  O25  1  0.133  0.133  0.088  1.0
  O  O26  1  0.231  0.231  0.382  1.0
  O  O27  1  0.612  0.612  0.650  1.0
[/CIF]
.