The material described by CaNaAlSi2O7 crystallizes in the orthorhombic P2_12_12_1 space group. Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(7), two equivalent O(4), and two equivalent O(6) atoms. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(6), one O(7), and two equivalent O(5) atoms. Al(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form AlO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Ca(1), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Ca(1), one Al(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Na(1), one Ca(1), one Al(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Na(1), one Al(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1), one Al(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Ca(1), and one Si(1) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Na(1), one Ca(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaCaAlSi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.697
_cell_length_b   7.769
_cell_length_c   9.891
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   591.504
_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
  Na  Na0  1  0.604  0.340  0.007  1.0
  Na  Na1  1  0.396  0.840  0.493  1.0
  Na  Na2  1  0.896  0.660  0.507  1.0
  Na  Na3  1  0.104  0.160  0.993  1.0
  Ca  Ca4  1  0.872  0.620  0.053  1.0
  Ca  Ca5  1  0.128  0.120  0.447  1.0
  Ca  Ca6  1  0.628  0.380  0.553  1.0
  Ca  Ca7  1  0.372  0.880  0.947  1.0
  Al  Al8  1  0.758  0.000  1.000  1.0
  Al  Al9  1  0.742  1.000  0.500  1.0
  Al  Al10  1  0.242  0.500  0.500  1.0
  Al  Al11  1  0.258  0.500  0.000  1.0
  Si  Si12  1  0.389  0.144  0.683  1.0
  Si  Si13  1  0.095  0.849  0.683  1.0
  Si  Si14  1  0.905  0.349  0.817  1.0
  Si  Si15  1  0.611  0.644  0.817  1.0
  Si  Si16  1  0.111  0.856  0.183  1.0
  Si  Si17  1  0.405  0.151  0.183  1.0
  Si  Si18  1  0.889  0.356  0.317  1.0
  Si  Si19  1  0.595  0.651  0.317  1.0
  O  O20  1  0.254  0.003  0.134  1.0
  O  O21  1  0.926  0.912  0.105  1.0
  O  O22  1  0.578  0.076  0.099  1.0
  O  O23  1  0.338  0.328  0.102  1.0
  O  O24  1  0.173  0.677  0.102  1.0
  O  O25  1  0.899  0.353  0.157  1.0
  O  O26  1  0.599  0.659  0.157  1.0
  O  O27  1  0.401  0.159  0.343  1.0
  O  O28  1  0.101  0.853  0.343  1.0
  O  O29  1  0.662  0.828  0.398  1.0
  O  O30  1  0.422  0.576  0.401  1.0
  O  O31  1  0.074  0.412  0.395  1.0
  O  O32  1  0.827  0.177  0.398  1.0
  O  O33  1  0.746  0.503  0.366  1.0
  O  O34  1  0.246  0.997  0.634  1.0
  O  O35  1  0.574  0.088  0.605  1.0
  O  O36  1  0.327  0.323  0.602  1.0
  O  O37  1  0.162  0.672  0.602  1.0
  O  O38  1  0.922  0.924  0.599  1.0
  O  O39  1  0.901  0.341  0.657  1.0
  O  O40  1  0.601  0.647  0.657  1.0
  O  O41  1  0.099  0.841  0.843  1.0
  O  O42  1  0.399  0.147  0.843  1.0
  O  O43  1  0.673  0.823  0.898  1.0
  O  O44  1  0.426  0.588  0.895  1.0
  O  O45  1  0.078  0.424  0.901  1.0
  O  O46  1  0.838  0.172  0.898  1.0
  O  O47  1  0.754  0.497  0.866  1.0
[/CIF]
.
The material described by CaNaAlSi2O7 crystallizes in the orthorhombic P2_12_12_1 space group. Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(7), two equivalent O(4), and two equivalent O(6) atoms. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(6), one O(7), and two equivalent O(5) atoms. Al(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form AlO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Al(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Ca(1), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Ca(1), one Al(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Na(1), one Ca(1), one Al(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Na(1), one Al(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1), one Al(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Ca(1), and one Si(1) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Na(1), one Ca(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaCaAlSi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.697
_cell_length_b   7.769
_cell_length_c   9.891
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   591.504
_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
  Na  Na0  1  0.604  0.340  0.007  1.0
  Na  Na1  1  0.396  0.840  0.493  1.0
  Na  Na2  1  0.896  0.660  0.507  1.0
  Na  Na3  1  0.104  0.160  0.993  1.0
  Ca  Ca4  1  0.872  0.620  0.053  1.0
  Ca  Ca5  1  0.128  0.120  0.447  1.0
  Ca  Ca6  1  0.628  0.380  0.553  1.0
  Ca  Ca7  1  0.372  0.880  0.947  1.0
  Al  Al8  1  0.758  0.000  1.000  1.0
  Al  Al9  1  0.742  1.000  0.500  1.0
  Al  Al10  1  0.242  0.500  0.500  1.0
  Al  Al11  1  0.258  0.500  0.000  1.0
  Si  Si12  1  0.389  0.144  0.683  1.0
  Si  Si13  1  0.095  0.849  0.683  1.0
  Si  Si14  1  0.905  0.349  0.817  1.0
  Si  Si15  1  0.611  0.644  0.817  1.0
  Si  Si16  1  0.111  0.856  0.183  1.0
  Si  Si17  1  0.405  0.151  0.183  1.0
  Si  Si18  1  0.889  0.356  0.317  1.0
  Si  Si19  1  0.595  0.651  0.317  1.0
  O  O20  1  0.254  0.003  0.134  1.0
  O  O21  1  0.926  0.912  0.105  1.0
  O  O22  1  0.578  0.076  0.099  1.0
  O  O23  1  0.338  0.328  0.102  1.0
  O  O24  1  0.173  0.677  0.102  1.0
  O  O25  1  0.899  0.353  0.157  1.0
  O  O26  1  0.599  0.659  0.157  1.0
  O  O27  1  0.401  0.159  0.343  1.0
  O  O28  1  0.101  0.853  0.343  1.0
  O  O29  1  0.662  0.828  0.398  1.0
  O  O30  1  0.422  0.576  0.401  1.0
  O  O31  1  0.074  0.412  0.395  1.0
  O  O32  1  0.827  0.177  0.398  1.0
  O  O33  1  0.746  0.503  0.366  1.0
  O  O34  1  0.246  0.997  0.634  1.0
  O  O35  1  0.574  0.088  0.605  1.0
  O  O36  1  0.327  0.323  0.602  1.0
  O  O37  1  0.162  0.672  0.602  1.0
  O  O38  1  0.922  0.924  0.599  1.0
  O  O39  1  0.901  0.341  0.657  1.0
  O  O40  1  0.601  0.647  0.657  1.0
  O  O41  1  0.099  0.841  0.843  1.0
  O  O42  1  0.399  0.147  0.843  1.0
  O  O43  1  0.673  0.823  0.898  1.0
  O  O44  1  0.426  0.588  0.895  1.0
  O  O45  1  0.078  0.424  0.901  1.0
  O  O46  1  0.838  0.172  0.898  1.0
  O  O47  1  0.754  0.497  0.866  1.0
[/CIF]
.