The structure described by NaAlSiO4 crystallizes in the orthorhombic Pmc2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(5), and two equivalent O(7) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(4), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form AlO6 octahedra that share corners with four equivalent Si(2)O6 octahedra, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. In the second Al site, Al(2) is bonded to one O(2), one O(6), two equivalent O(5), and two equivalent O(8) atoms to form AlO6 octahedra that share corners with four equivalent Si(1)O6 octahedra, edges with two equivalent Al(2)O6 octahedra, and edges with two equivalent Si(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-53°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(8), two equivalent O(2), and two equivalent O(4) atoms to form SiO6 octahedra that share corners with four equivalent Al(2)O6 octahedra, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-53°. In the second Si site, Si(2) is bonded to one O(1), one O(5), two equivalent O(6), and two equivalent O(7) atoms to form SiO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, edges with two equivalent Al(2)O6 octahedra, and edges with two equivalent Si(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(2), two equivalent Al(1), and one Si(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Al(2), and two equivalent Si(1) atoms. In the third O site, O(3) is bonded to two equivalent Na(2), two equivalent Al(1), and one Si(1) atom to form distorted ONa2Al2Si trigonal bipyramids that share  a cornercorner with one O(8)Na2Al2Si trigonal bipyramid, corners with two equivalent O(5)Na2Al2Si trigonal bipyramids,  an edgeedge with one O(5)Na2Al2Si trigonal bipyramid, edges with two equivalent O(3)Na2Al2Si trigonal bipyramids, and edges with two equivalent O(4)Na2AlSi2 trigonal bipyramids. In the fourth O site, O(4) is bonded to two equivalent Na(1), one Al(1), and two equivalent Si(1) atoms to form distorted ONa2AlSi2 trigonal bipyramids that share corners with two equivalent O(6)Na2AlSi2 square pyramids, corners with two equivalent O(8)Na2Al2Si trigonal bipyramids,  an edgeedge with one O(6)Na2AlSi2 square pyramid, edges with two equivalent O(3)Na2Al2Si trigonal bipyramids, edges with two equivalent O(8)Na2Al2Si trigonal bipyramids, and edges with two equivalent O(4)Na2AlSi2 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Na(2), two equivalent Al(2), and one Si(2) atom to form distorted ONa2Al2Si trigonal bipyramids that share corners with two equivalent O(3)Na2Al2Si trigonal bipyramids, corners with two equivalent O(8)Na2Al2Si trigonal bipyramids, edges with two equivalent O(6)Na2AlSi2 square pyramids,  an edgeedge with one O(3)Na2Al2Si trigonal bipyramid,  an edgeedge with one O(8)Na2Al2Si trigonal bipyramid, and edges with two equivalent O(5)Na2Al2Si trigonal bipyramids. In the sixth O site, O(6) is bonded to two equivalent Na(1), one Al(2), and two equivalent Si(2) atoms to form ONa2AlSi2 square pyramids that share corners with two equivalent O(8)Na2Al2Si trigonal bipyramids, corners with two equivalent O(4)Na2AlSi2 trigonal bipyramids, edges with two equivalent O(6)Na2AlSi2 square pyramids,  an edgeedge with one O(4)Na2AlSi2 trigonal bipyramid, edges with two equivalent O(5)Na2Al2Si trigonal bipyramids, and edges with two equivalent O(8)Na2Al2Si trigonal bipyramids. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to two equivalent Na(2), one Al(1), and two equivalent Si(2) atoms. In the eighth O site, O(8) is bonded to two equivalent Na(1), two equivalent Al(2), and one Si(1) atom to form distorted ONa2Al2Si trigonal bipyramids that share corners with two equivalent O(6)Na2AlSi2 square pyramids,  a cornercorner with one O(3)Na2Al2Si trigonal bipyramid, corners with two equivalent O(5)Na2Al2Si trigonal bipyramids, corners with two equivalent O(4)Na2AlSi2 trigonal bipyramids, corners with four equivalent O(8)Na2Al2Si trigonal bipyramids, edges with two equivalent O(6)Na2AlSi2 square pyramids,  an edgeedge with one O(5)Na2Al2Si trigonal bipyramid, and edges with two equivalent O(4)Na2AlSi2 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaAlSiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.766
_cell_length_b   8.775
_cell_length_c   10.222
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   248.142
_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  0.250  0.739  0.162  1.0
  Na  Na1  1  0.250  0.239  0.338  1.0
  Na  Na2  1  0.750  0.257  0.846  1.0
  Na  Na3  1  0.750  0.757  0.654  1.0
  Al  Al4  1  0.750  0.934  0.889  1.0
  Al  Al5  1  0.750  0.434  0.611  1.0
  Al  Al6  1  0.750  0.922  0.397  1.0
  Al  Al7  1  0.750  0.422  0.103  1.0
  Si  Si8  1  0.250  0.053  0.111  1.0
  Si  Si9  1  0.250  0.553  0.389  1.0
  Si  Si10  1  0.250  0.086  0.600  1.0
  Si  Si11  1  0.250  0.586  0.900  1.0
  O  O12  1  0.250  0.789  0.851  1.0
  O  O13  1  0.250  0.289  0.649  1.0
  O  O14  1  0.750  0.191  0.143  1.0
  O  O15  1  0.750  0.691  0.357  1.0
  O  O16  1  0.250  0.071  0.936  1.0
  O  O17  1  0.250  0.571  0.564  1.0
  O  O18  1  0.750  0.924  0.080  1.0
  O  O19  1  0.750  0.424  0.420  1.0
  O  O20  1  0.250  0.898  0.520  1.0
  O  O21  1  0.250  0.398  0.980  1.0
  O  O22  1  0.750  0.123  0.489  1.0
  O  O23  1  0.750  0.623  0.011  1.0
  O  O24  1  0.750  0.033  0.709  1.0
  O  O25  1  0.750  0.533  0.791  1.0
  O  O26  1  0.250  0.980  0.281  1.0
  O  O27  1  0.250  0.480  0.219  1.0
[/CIF]
.
The structure described by NaAlSiO4 crystallizes in the orthorhombic Pmc2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(5), and two equivalent O(7) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(4), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form AlO6 octahedra that share corners with four equivalent Si(2)O6 octahedra, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. In the second Al site, Al(2) is bonded to one O(2), one O(6), two equivalent O(5), and two equivalent O(8) atoms to form AlO6 octahedra that share corners with four equivalent Si(1)O6 octahedra, edges with two equivalent Al(2)O6 octahedra, and edges with two equivalent Si(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-53°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(8), two equivalent O(2), and two equivalent O(4) atoms to form SiO6 octahedra that share corners with four equivalent Al(2)O6 octahedra, edges with two equivalent Al(1)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-53°. In the second Si site, Si(2) is bonded to one O(1), one O(5), two equivalent O(6), and two equivalent O(7) atoms to form SiO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, edges with two equivalent Al(2)O6 octahedra, and edges with two equivalent Si(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(2), two equivalent Al(1), and one Si(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Al(2), and two equivalent Si(1) atoms. In the third O site, O(3) is bonded to two equivalent Na(2), two equivalent Al(1), and one Si(1) atom to form distorted ONa2Al2Si trigonal bipyramids that share  a cornercorner with one O(8)Na2Al2Si trigonal bipyramid, corners with two equivalent O(5)Na2Al2Si trigonal bipyramids,  an edgeedge with one O(5)Na2Al2Si trigonal bipyramid, edges with two equivalent O(3)Na2Al2Si trigonal bipyramids, and edges with two equivalent O(4)Na2AlSi2 trigonal bipyramids. In the fourth O site, O(4) is bonded to two equivalent Na(1), one Al(1), and two equivalent Si(1) atoms to form distorted ONa2AlSi2 trigonal bipyramids that share corners with two equivalent O(6)Na2AlSi2 square pyramids, corners with two equivalent O(8)Na2Al2Si trigonal bipyramids,  an edgeedge with one O(6)Na2AlSi2 square pyramid, edges with two equivalent O(3)Na2Al2Si trigonal bipyramids, edges with two equivalent O(8)Na2Al2Si trigonal bipyramids, and edges with two equivalent O(4)Na2AlSi2 trigonal bipyramids. In the fifth O site, O(5) is bonded to two equivalent Na(2), two equivalent Al(2), and one Si(2) atom to form distorted ONa2Al2Si trigonal bipyramids that share corners with two equivalent O(3)Na2Al2Si trigonal bipyramids, corners with two equivalent O(8)Na2Al2Si trigonal bipyramids, edges with two equivalent O(6)Na2AlSi2 square pyramids,  an edgeedge with one O(3)Na2Al2Si trigonal bipyramid,  an edgeedge with one O(8)Na2Al2Si trigonal bipyramid, and edges with two equivalent O(5)Na2Al2Si trigonal bipyramids. In the sixth O site, O(6) is bonded to two equivalent Na(1), one Al(2), and two equivalent Si(2) atoms to form ONa2AlSi2 square pyramids that share corners with two equivalent O(8)Na2Al2Si trigonal bipyramids, corners with two equivalent O(4)Na2AlSi2 trigonal bipyramids, edges with two equivalent O(6)Na2AlSi2 square pyramids,  an edgeedge with one O(4)Na2AlSi2 trigonal bipyramid, edges with two equivalent O(5)Na2Al2Si trigonal bipyramids, and edges with two equivalent O(8)Na2Al2Si trigonal bipyramids. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to two equivalent Na(2), one Al(1), and two equivalent Si(2) atoms. In the eighth O site, O(8) is bonded to two equivalent Na(1), two equivalent Al(2), and one Si(1) atom to form distorted ONa2Al2Si trigonal bipyramids that share corners with two equivalent O(6)Na2AlSi2 square pyramids,  a cornercorner with one O(3)Na2Al2Si trigonal bipyramid, corners with two equivalent O(5)Na2Al2Si trigonal bipyramids, corners with two equivalent O(4)Na2AlSi2 trigonal bipyramids, corners with four equivalent O(8)Na2Al2Si trigonal bipyramids, edges with two equivalent O(6)Na2AlSi2 square pyramids,  an edgeedge with one O(5)Na2Al2Si trigonal bipyramid, and edges with two equivalent O(4)Na2AlSi2 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaAlSiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.766
_cell_length_b   8.775
_cell_length_c   10.222
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   248.142
_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  0.250  0.739  0.162  1.0
  Na  Na1  1  0.250  0.239  0.338  1.0
  Na  Na2  1  0.750  0.257  0.846  1.0
  Na  Na3  1  0.750  0.757  0.654  1.0
  Al  Al4  1  0.750  0.934  0.889  1.0
  Al  Al5  1  0.750  0.434  0.611  1.0
  Al  Al6  1  0.750  0.922  0.397  1.0
  Al  Al7  1  0.750  0.422  0.103  1.0
  Si  Si8  1  0.250  0.053  0.111  1.0
  Si  Si9  1  0.250  0.553  0.389  1.0
  Si  Si10  1  0.250  0.086  0.600  1.0
  Si  Si11  1  0.250  0.586  0.900  1.0
  O  O12  1  0.250  0.789  0.851  1.0
  O  O13  1  0.250  0.289  0.649  1.0
  O  O14  1  0.750  0.191  0.143  1.0
  O  O15  1  0.750  0.691  0.357  1.0
  O  O16  1  0.250  0.071  0.936  1.0
  O  O17  1  0.250  0.571  0.564  1.0
  O  O18  1  0.750  0.924  0.080  1.0
  O  O19  1  0.750  0.424  0.420  1.0
  O  O20  1  0.250  0.898  0.520  1.0
  O  O21  1  0.250  0.398  0.980  1.0
  O  O22  1  0.750  0.123  0.489  1.0
  O  O23  1  0.750  0.623  0.011  1.0
  O  O24  1  0.750  0.033  0.709  1.0
  O  O25  1  0.750  0.533  0.791  1.0
  O  O26  1  0.250  0.980  0.281  1.0
  O  O27  1  0.250  0.480  0.219  1.0
[/CIF]
.