The crystal structure described by Ca3Co4O9 crystallizes in the orthorhombic Cmm2 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(2) and four equivalent O(7) atoms to form distorted CaO6 pentagonal pyramids that share corners with eight equivalent Co(1)O4 tetrahedra. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(6), one O(8), two equivalent O(1), two equivalent O(3), and two equivalent O(9) atoms. In the third Ca site, Ca(3) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(4), one O(5), one O(7), and one O(8) atom. In the fourth Ca site, Ca(4) is bonded in a 8-coordinate geometry to one O(1), one O(2), two equivalent O(5), two equivalent O(7), and two equivalent O(9) atoms. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form CoO4 tetrahedra that share corners with two equivalent Ca(1)O6 pentagonal pyramids,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(4)O4 tetrahedra, and corners with two equivalent Co(1)O4 tetrahedra. In the second Co site, Co(2) is bonded to one O(10), one O(3), one O(5), and one O(9) atom to form corner-sharing CoO4 tetrahedra. In the third Co site, Co(3) is bonded to one O(1), one O(6), and two equivalent O(9) atoms to form distorted corner-sharing CoO4 tetrahedra. In the fourth Co site, Co(4) is bonded to one O(4), one O(8), and two equivalent O(3) atoms to form corner-sharing CoO4 tetrahedra. There are ten inequivalent O sites. In the first O site, O(10) is bonded to two equivalent Ca(3) and two equivalent Co(2) atoms to form OCa2Co2 tetrahedra that share corners with two equivalent O(7)Ca3Co tetrahedra, corners with two equivalent O(8)Ca3Co tetrahedra, and corners with four equivalent O(3)Ca2Co2 tetrahedra. In the second O site, O(1) is bonded to one Ca(4), two equivalent Ca(2), and one Co(3) atom to form OCa3Co tetrahedra that share  a cornercorner with one O(2)Ca2Co2 tetrahedra,  a cornercorner with one O(6)Ca2Co2 tetrahedra, corners with two equivalent O(7)Ca3Co tetrahedra, corners with two equivalent O(8)Ca3Co tetrahedra, corners with four equivalent O(3)Ca2Co2 tetrahedra,  an edgeedge with one O(6)Ca2Co2 tetrahedra, and  an edgeedge with one O(1)Ca3Co tetrahedra. In the third O site, O(2) is bonded to one Ca(1), one Ca(4), and two equivalent Co(1) atoms to form OCa2Co2 tetrahedra that share  a cornercorner with one O(2)Ca2Co2 tetrahedra,  a cornercorner with one O(1)Ca3Co tetrahedra, corners with four equivalent O(7)Ca3Co tetrahedra, and edges with two equivalent O(7)Ca3Co tetrahedra. In the fourth O site, O(3) is bonded to one Ca(2), one Ca(3), one Co(2), and one Co(4) atom to form distorted OCa2Co2 tetrahedra that share  a cornercorner with one O(6)Ca2Co2 tetrahedra,  a cornercorner with one O(7)Ca3Co tetrahedra,  a cornercorner with one O(8)Ca3Co tetrahedra, corners with two equivalent O(10)Ca2Co2 tetrahedra, corners with two equivalent O(1)Ca3Co tetrahedra,  an edgeedge with one O(3)Ca2Co2 tetrahedra, and  an edgeedge with one O(8)Ca3Co tetrahedra. In the fifth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Ca(3), one Co(4), and two equivalent Co(1) atoms. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(3), one Ca(4), one Co(1), and one Co(2) atom. In the seventh O site, O(6) is bonded to two equivalent Ca(2) and two equivalent Co(3) atoms to form OCa2Co2 tetrahedra that share corners with two equivalent O(1)Ca3Co tetrahedra, corners with two equivalent O(8)Ca3Co tetrahedra, corners with four equivalent O(3)Ca2Co2 tetrahedra, and edges with two equivalent O(1)Ca3Co tetrahedra. In the eighth O site, O(7) is bonded to one Ca(1), one Ca(3), one Ca(4), and one Co(1) atom to form distorted OCa3Co tetrahedra that share  a cornercorner with one O(10)Ca2Co2 tetrahedra,  a cornercorner with one O(3)Ca2Co2 tetrahedra,  a cornercorner with one O(1)Ca3Co tetrahedra,  a cornercorner with one O(8)Ca3Co tetrahedra, corners with two equivalent O(2)Ca2Co2 tetrahedra, corners with two equivalent O(7)Ca3Co tetrahedra,  an edgeedge with one O(2)Ca2Co2 tetrahedra, and  an edgeedge with one O(7)Ca3Co tetrahedra. In the ninth O site, O(8) is bonded to one Ca(2), two equivalent Ca(3), and one Co(4) atom to form distorted OCa3Co tetrahedra that share  a cornercorner with one O(6)Ca2Co2 tetrahedra, corners with two equivalent O(10)Ca2Co2 tetrahedra, corners with two equivalent O(3)Ca2Co2 tetrahedra, corners with two equivalent O(1)Ca3Co tetrahedra, corners with two equivalent O(7)Ca3Co tetrahedra, and edges with two equivalent O(3)Ca2Co2 tetrahedra. In the tenth O site, O(9) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(4), one Co(2), and one Co(3) atom. is represented by the CIF card [CIF]
data_Ca3Co4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.329
_cell_length_b   11.157
_cell_length_c   11.157
_cell_angle_alpha   99.006
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   655.113
_cell_formula_units_Z   3
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  0.002  0.000  0.000  1.0
  Ca  Ca1  1  0.087  0.401  0.599  1.0
  Ca  Ca2  1  0.087  0.599  0.401  1.0
  Ca  Ca3  1  0.040  0.082  0.659  1.0
  Ca  Ca4  1  0.040  0.918  0.341  1.0
  Ca  Ca5  1  0.040  0.341  0.918  1.0
  Ca  Ca6  1  0.040  0.659  0.082  1.0
  Ca  Ca7  1  0.054  0.760  0.760  1.0
  Ca  Ca8  1  0.054  0.240  0.240  1.0
  Co  Co9  1  0.515  0.983  0.796  1.0
  Co  Co10  1  0.515  0.017  0.204  1.0
  Co  Co11  1  0.515  0.204  0.017  1.0
  Co  Co12  1  0.515  0.796  0.983  1.0
  Co  Co13  1  0.566  0.134  0.463  1.0
  Co  Co14  1  0.566  0.866  0.537  1.0
  Co  Co15  1  0.566  0.537  0.866  1.0
  Co  Co16  1  0.566  0.463  0.134  1.0
  Co  Co17  1  0.601  0.615  0.615  1.0
  Co  Co18  1  0.601  0.385  0.385  1.0
  Co  Co19  1  0.527  0.264  0.736  1.0
  Co  Co20  1  0.527  0.736  0.264  1.0
  O  O21  1  0.269  0.607  0.607  1.0
  O  O22  1  0.269  0.393  0.393  1.0
  O  O23  1  0.329  0.894  0.894  1.0
  O  O24  1  0.329  0.106  0.106  1.0
  O  O25  1  0.351  0.209  0.592  1.0
  O  O26  1  0.351  0.791  0.408  1.0
  O  O27  1  0.351  0.408  0.791  1.0
  O  O28  1  0.351  0.592  0.209  1.0
  O  O29  1  0.405  0.154  0.846  1.0
  O  O30  1  0.405  0.846  0.154  1.0
  O  O31  1  0.330  0.069  0.348  1.0
  O  O32  1  0.330  0.931  0.652  1.0
  O  O33  1  0.330  0.652  0.931  1.0
  O  O34  1  0.330  0.348  0.069  1.0
  O  O35  1  0.779  0.500  0.500  1.0
  O  O36  1  0.846  0.977  0.797  1.0
  O  O37  1  0.846  0.023  0.203  1.0
  O  O38  1  0.846  0.203  0.023  1.0
  O  O39  1  0.846  0.797  0.977  1.0
  O  O40  1  0.861  0.270  0.730  1.0
  O  O41  1  0.861  0.730  0.270  1.0
  O  O42  1  0.775  0.247  0.418  1.0
  O  O43  1  0.775  0.753  0.582  1.0
  O  O44  1  0.775  0.582  0.753  1.0
  O  O45  1  0.775  0.418  0.247  1.0
  O  O46  1  0.760  0.000  0.500  1.0
  O  O47  1  0.760  0.500  0.000  1.0
[/CIF]
.
The crystal structure described by Ca3Co4O9 crystallizes in the orthorhombic Cmm2 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(2) and four equivalent O(7) atoms to form distorted CaO6 pentagonal pyramids that share corners with eight equivalent Co(1)O4 tetrahedra. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(6), one O(8), two equivalent O(1), two equivalent O(3), and two equivalent O(9) atoms. In the third Ca site, Ca(3) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(4), one O(5), one O(7), and one O(8) atom. In the fourth Ca site, Ca(4) is bonded in a 8-coordinate geometry to one O(1), one O(2), two equivalent O(5), two equivalent O(7), and two equivalent O(9) atoms. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form CoO4 tetrahedra that share corners with two equivalent Ca(1)O6 pentagonal pyramids,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(4)O4 tetrahedra, and corners with two equivalent Co(1)O4 tetrahedra. In the second Co site, Co(2) is bonded to one O(10), one O(3), one O(5), and one O(9) atom to form corner-sharing CoO4 tetrahedra. In the third Co site, Co(3) is bonded to one O(1), one O(6), and two equivalent O(9) atoms to form distorted corner-sharing CoO4 tetrahedra. In the fourth Co site, Co(4) is bonded to one O(4), one O(8), and two equivalent O(3) atoms to form corner-sharing CoO4 tetrahedra. There are ten inequivalent O sites. In the first O site, O(10) is bonded to two equivalent Ca(3) and two equivalent Co(2) atoms to form OCa2Co2 tetrahedra that share corners with two equivalent O(7)Ca3Co tetrahedra, corners with two equivalent O(8)Ca3Co tetrahedra, and corners with four equivalent O(3)Ca2Co2 tetrahedra. In the second O site, O(1) is bonded to one Ca(4), two equivalent Ca(2), and one Co(3) atom to form OCa3Co tetrahedra that share  a cornercorner with one O(2)Ca2Co2 tetrahedra,  a cornercorner with one O(6)Ca2Co2 tetrahedra, corners with two equivalent O(7)Ca3Co tetrahedra, corners with two equivalent O(8)Ca3Co tetrahedra, corners with four equivalent O(3)Ca2Co2 tetrahedra,  an edgeedge with one O(6)Ca2Co2 tetrahedra, and  an edgeedge with one O(1)Ca3Co tetrahedra. In the third O site, O(2) is bonded to one Ca(1), one Ca(4), and two equivalent Co(1) atoms to form OCa2Co2 tetrahedra that share  a cornercorner with one O(2)Ca2Co2 tetrahedra,  a cornercorner with one O(1)Ca3Co tetrahedra, corners with four equivalent O(7)Ca3Co tetrahedra, and edges with two equivalent O(7)Ca3Co tetrahedra. In the fourth O site, O(3) is bonded to one Ca(2), one Ca(3), one Co(2), and one Co(4) atom to form distorted OCa2Co2 tetrahedra that share  a cornercorner with one O(6)Ca2Co2 tetrahedra,  a cornercorner with one O(7)Ca3Co tetrahedra,  a cornercorner with one O(8)Ca3Co tetrahedra, corners with two equivalent O(10)Ca2Co2 tetrahedra, corners with two equivalent O(1)Ca3Co tetrahedra,  an edgeedge with one O(3)Ca2Co2 tetrahedra, and  an edgeedge with one O(8)Ca3Co tetrahedra. In the fifth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Ca(3), one Co(4), and two equivalent Co(1) atoms. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(3), one Ca(4), one Co(1), and one Co(2) atom. In the seventh O site, O(6) is bonded to two equivalent Ca(2) and two equivalent Co(3) atoms to form OCa2Co2 tetrahedra that share corners with two equivalent O(1)Ca3Co tetrahedra, corners with two equivalent O(8)Ca3Co tetrahedra, corners with four equivalent O(3)Ca2Co2 tetrahedra, and edges with two equivalent O(1)Ca3Co tetrahedra. In the eighth O site, O(7) is bonded to one Ca(1), one Ca(3), one Ca(4), and one Co(1) atom to form distorted OCa3Co tetrahedra that share  a cornercorner with one O(10)Ca2Co2 tetrahedra,  a cornercorner with one O(3)Ca2Co2 tetrahedra,  a cornercorner with one O(1)Ca3Co tetrahedra,  a cornercorner with one O(8)Ca3Co tetrahedra, corners with two equivalent O(2)Ca2Co2 tetrahedra, corners with two equivalent O(7)Ca3Co tetrahedra,  an edgeedge with one O(2)Ca2Co2 tetrahedra, and  an edgeedge with one O(7)Ca3Co tetrahedra. In the ninth O site, O(8) is bonded to one Ca(2), two equivalent Ca(3), and one Co(4) atom to form distorted OCa3Co tetrahedra that share  a cornercorner with one O(6)Ca2Co2 tetrahedra, corners with two equivalent O(10)Ca2Co2 tetrahedra, corners with two equivalent O(3)Ca2Co2 tetrahedra, corners with two equivalent O(1)Ca3Co tetrahedra, corners with two equivalent O(7)Ca3Co tetrahedra, and edges with two equivalent O(3)Ca2Co2 tetrahedra. In the tenth O site, O(9) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(4), one Co(2), and one Co(3) atom. is represented by the CIF card [CIF]
data_Ca3Co4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.329
_cell_length_b   11.157
_cell_length_c   11.157
_cell_angle_alpha   99.006
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   655.113
_cell_formula_units_Z   3
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  0.002  0.000  0.000  1.0
  Ca  Ca1  1  0.087  0.401  0.599  1.0
  Ca  Ca2  1  0.087  0.599  0.401  1.0
  Ca  Ca3  1  0.040  0.082  0.659  1.0
  Ca  Ca4  1  0.040  0.918  0.341  1.0
  Ca  Ca5  1  0.040  0.341  0.918  1.0
  Ca  Ca6  1  0.040  0.659  0.082  1.0
  Ca  Ca7  1  0.054  0.760  0.760  1.0
  Ca  Ca8  1  0.054  0.240  0.240  1.0
  Co  Co9  1  0.515  0.983  0.796  1.0
  Co  Co10  1  0.515  0.017  0.204  1.0
  Co  Co11  1  0.515  0.204  0.017  1.0
  Co  Co12  1  0.515  0.796  0.983  1.0
  Co  Co13  1  0.566  0.134  0.463  1.0
  Co  Co14  1  0.566  0.866  0.537  1.0
  Co  Co15  1  0.566  0.537  0.866  1.0
  Co  Co16  1  0.566  0.463  0.134  1.0
  Co  Co17  1  0.601  0.615  0.615  1.0
  Co  Co18  1  0.601  0.385  0.385  1.0
  Co  Co19  1  0.527  0.264  0.736  1.0
  Co  Co20  1  0.527  0.736  0.264  1.0
  O  O21  1  0.269  0.607  0.607  1.0
  O  O22  1  0.269  0.393  0.393  1.0
  O  O23  1  0.329  0.894  0.894  1.0
  O  O24  1  0.329  0.106  0.106  1.0
  O  O25  1  0.351  0.209  0.592  1.0
  O  O26  1  0.351  0.791  0.408  1.0
  O  O27  1  0.351  0.408  0.791  1.0
  O  O28  1  0.351  0.592  0.209  1.0
  O  O29  1  0.405  0.154  0.846  1.0
  O  O30  1  0.405  0.846  0.154  1.0
  O  O31  1  0.330  0.069  0.348  1.0
  O  O32  1  0.330  0.931  0.652  1.0
  O  O33  1  0.330  0.652  0.931  1.0
  O  O34  1  0.330  0.348  0.069  1.0
  O  O35  1  0.779  0.500  0.500  1.0
  O  O36  1  0.846  0.977  0.797  1.0
  O  O37  1  0.846  0.023  0.203  1.0
  O  O38  1  0.846  0.203  0.023  1.0
  O  O39  1  0.846  0.797  0.977  1.0
  O  O40  1  0.861  0.270  0.730  1.0
  O  O41  1  0.861  0.730  0.270  1.0
  O  O42  1  0.775  0.247  0.418  1.0
  O  O43  1  0.775  0.753  0.582  1.0
  O  O44  1  0.775  0.582  0.753  1.0
  O  O45  1  0.775  0.418  0.247  1.0
  O  O46  1  0.760  0.000  0.500  1.0
  O  O47  1  0.760  0.500  0.000  1.0
[/CIF]
.