The compound described by CaCO3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted octahedral geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(4) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(5) and two equivalent O(3) atoms. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one C(2) atom. In the second O site, O(4) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one C(1) atom. In the third O site, O(5) is bonded in a trigonal planar geometry to two equivalent Ca(2) and one C(2) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ca(2) and one C(1) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one C(1) atom. is represented by the CIF file [CIF]
data_CaCO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.125
_cell_length_b   7.125
_cell_length_c   9.414
_cell_angle_alpha   68.340
_cell_angle_beta   68.340
_cell_angle_gamma   60.547
_symmetry_Int_Tables_number   1
_cell_volume   376.261
_cell_formula_units_Z   6
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  0.000  0.500  0.500  1.0
  Ca  Ca1  1  0.500  0.000  0.000  1.0
  Ca  Ca2  1  0.197  0.653  0.999  1.0
  Ca  Ca3  1  0.347  0.803  0.501  1.0
  Ca  Ca4  1  0.803  0.347  0.001  1.0
  Ca  Ca5  1  0.653  0.197  0.499  1.0
  C  C6  1  0.207  0.413  0.766  1.0
  C  C7  1  0.587  0.793  0.734  1.0
  C  C8  1  0.793  0.587  0.234  1.0
  C  C9  1  0.413  0.207  0.266  1.0
  C  C10  1  0.951  0.049  0.750  1.0
  C  C11  1  0.049  0.951  0.250  1.0
  O  O12  1  0.345  0.455  0.639  1.0
  O  O13  1  0.545  0.655  0.861  1.0
  O  O14  1  0.655  0.545  0.361  1.0
  O  O15  1  0.455  0.345  0.139  1.0
  O  O16  1  0.241  0.361  0.904  1.0
  O  O17  1  0.639  0.759  0.596  1.0
  O  O18  1  0.759  0.639  0.096  1.0
  O  O19  1  0.361  0.241  0.404  1.0
  O  O20  1  0.819  0.090  0.883  1.0
  O  O21  1  0.910  0.181  0.617  1.0
  O  O22  1  0.181  0.910  0.117  1.0
  O  O23  1  0.090  0.819  0.383  1.0
  O  O24  1  0.027  0.422  0.756  1.0
  O  O25  1  0.578  0.973  0.744  1.0
  O  O26  1  0.973  0.578  0.244  1.0
  O  O27  1  0.422  0.027  0.256  1.0
  O  O28  1  0.131  0.869  0.750  1.0
  O  O29  1  0.869  0.131  0.250  1.0
[/CIF]
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The compound described by CaCO3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted octahedral geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(4) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(5) and two equivalent O(3) atoms. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one C(2) atom. In the second O site, O(4) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one C(1) atom. In the third O site, O(5) is bonded in a trigonal planar geometry to two equivalent Ca(2) and one C(2) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ca(2) and one C(1) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one C(1) atom. is represented by the CIF file [CIF]
data_CaCO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.125
_cell_length_b   7.125
_cell_length_c   9.414
_cell_angle_alpha   68.340
_cell_angle_beta   68.340
_cell_angle_gamma   60.547
_symmetry_Int_Tables_number   1
_cell_volume   376.261
_cell_formula_units_Z   6
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  0.000  0.500  0.500  1.0
  Ca  Ca1  1  0.500  0.000  0.000  1.0
  Ca  Ca2  1  0.197  0.653  0.999  1.0
  Ca  Ca3  1  0.347  0.803  0.501  1.0
  Ca  Ca4  1  0.803  0.347  0.001  1.0
  Ca  Ca5  1  0.653  0.197  0.499  1.0
  C  C6  1  0.207  0.413  0.766  1.0
  C  C7  1  0.587  0.793  0.734  1.0
  C  C8  1  0.793  0.587  0.234  1.0
  C  C9  1  0.413  0.207  0.266  1.0
  C  C10  1  0.951  0.049  0.750  1.0
  C  C11  1  0.049  0.951  0.250  1.0
  O  O12  1  0.345  0.455  0.639  1.0
  O  O13  1  0.545  0.655  0.861  1.0
  O  O14  1  0.655  0.545  0.361  1.0
  O  O15  1  0.455  0.345  0.139  1.0
  O  O16  1  0.241  0.361  0.904  1.0
  O  O17  1  0.639  0.759  0.596  1.0
  O  O18  1  0.759  0.639  0.096  1.0
  O  O19  1  0.361  0.241  0.404  1.0
  O  O20  1  0.819  0.090  0.883  1.0
  O  O21  1  0.910  0.181  0.617  1.0
  O  O22  1  0.181  0.910  0.117  1.0
  O  O23  1  0.090  0.819  0.383  1.0
  O  O24  1  0.027  0.422  0.756  1.0
  O  O25  1  0.578  0.973  0.744  1.0
  O  O26  1  0.973  0.578  0.244  1.0
  O  O27  1  0.422  0.027  0.256  1.0
  O  O28  1  0.131  0.869  0.750  1.0
  O  O29  1  0.869  0.131  0.250  1.0
[/CIF]
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