The material structure described by Na2Al2B2O7 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form NaO6 octahedra that share corners with three equivalent Al(1)O4 tetrahedra and corners with three equivalent Al(2)O4 tetrahedra. In the second Na site, Na(2) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), and three equivalent O(1) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form AlO4 tetrahedra that share corners with three equivalent Na(1)O6 octahedra and  a cornercorner with one Al(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 65-68°. In the second Al site, Al(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AlO4 tetrahedra that share corners with three equivalent Na(1)O6 octahedra and  a cornercorner with one Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-67°. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(5), one O(6), and one O(7) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(4) atom. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 2-coordinate geometry to one Na(1), one Na(2), one Al(1), and one B(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Al(1), and one B(1) atom. In the third O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(1), and one B(1) atom. In the fourth O site, O(1) is bonded in a distorted linear geometry to three equivalent Na(2), one Al(1), and one Al(2) atom. In the fifth O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(2), and one B(2) atom. In the sixth O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(2), and one B(2) atom. In the seventh O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Al(2), and one B(2) atom. is represented by the CIF card [CIF]
data_Na2Al2B2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.865
_cell_length_b   4.865
_cell_length_c   15.575
_cell_angle_alpha   89.956
_cell_angle_beta   89.956
_cell_angle_gamma   119.675
_symmetry_Int_Tables_number   1
_cell_volume   320.269
_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
  Na  Na0  1  0.998  0.999  0.500  1.0
  Na  Na1  1  0.999  0.998  0.000  1.0
  Na  Na2  1  0.004  0.008  0.250  1.0
  Na  Na3  1  0.008  0.004  0.750  1.0
  Al  Al4  1  0.322  0.661  0.861  1.0
  Al  Al5  1  0.661  0.322  0.361  1.0
  Al  Al6  1  0.663  0.323  0.139  1.0
  Al  Al7  1  0.323  0.663  0.639  1.0
  B  B8  1  0.332  0.664  0.396  1.0
  B  B9  1  0.664  0.332  0.896  1.0
  B  B10  1  0.664  0.331  0.604  1.0
  B  B11  1  0.331  0.664  0.104  1.0
  O  O12  1  0.646  0.291  0.250  1.0
  O  O13  1  0.291  0.646  0.750  1.0
  O  O14  1  0.392  0.355  0.605  1.0
  O  O15  1  0.642  0.037  0.608  1.0
  O  O16  1  0.957  0.601  0.599  1.0
  O  O17  1  0.037  0.642  0.108  1.0
  O  O18  1  0.355  0.392  0.105  1.0
  O  O19  1  0.601  0.957  0.099  1.0
  O  O20  1  0.604  0.641  0.392  1.0
  O  O21  1  0.355  0.958  0.401  1.0
  O  O22  1  0.038  0.393  0.394  1.0
  O  O23  1  0.958  0.355  0.901  1.0
  O  O24  1  0.641  0.604  0.892  1.0
  O  O25  1  0.393  0.038  0.894  1.0
[/CIF]
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The material structure described by Na2Al2B2O7 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form NaO6 octahedra that share corners with three equivalent Al(1)O4 tetrahedra and corners with three equivalent Al(2)O4 tetrahedra. In the second Na site, Na(2) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), and three equivalent O(1) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form AlO4 tetrahedra that share corners with three equivalent Na(1)O6 octahedra and  a cornercorner with one Al(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 65-68°. In the second Al site, Al(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AlO4 tetrahedra that share corners with three equivalent Na(1)O6 octahedra and  a cornercorner with one Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-67°. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(5), one O(6), and one O(7) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(4) atom. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 2-coordinate geometry to one Na(1), one Na(2), one Al(1), and one B(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Al(1), and one B(1) atom. In the third O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(1), and one B(1) atom. In the fourth O site, O(1) is bonded in a distorted linear geometry to three equivalent Na(2), one Al(1), and one Al(2) atom. In the fifth O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(2), and one B(2) atom. In the sixth O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(2), and one B(2) atom. In the seventh O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Al(2), and one B(2) atom. is represented by the CIF card [CIF]
data_Na2Al2B2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.865
_cell_length_b   4.865
_cell_length_c   15.575
_cell_angle_alpha   89.956
_cell_angle_beta   89.956
_cell_angle_gamma   119.675
_symmetry_Int_Tables_number   1
_cell_volume   320.269
_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
  Na  Na0  1  0.998  0.999  0.500  1.0
  Na  Na1  1  0.999  0.998  0.000  1.0
  Na  Na2  1  0.004  0.008  0.250  1.0
  Na  Na3  1  0.008  0.004  0.750  1.0
  Al  Al4  1  0.322  0.661  0.861  1.0
  Al  Al5  1  0.661  0.322  0.361  1.0
  Al  Al6  1  0.663  0.323  0.139  1.0
  Al  Al7  1  0.323  0.663  0.639  1.0
  B  B8  1  0.332  0.664  0.396  1.0
  B  B9  1  0.664  0.332  0.896  1.0
  B  B10  1  0.664  0.331  0.604  1.0
  B  B11  1  0.331  0.664  0.104  1.0
  O  O12  1  0.646  0.291  0.250  1.0
  O  O13  1  0.291  0.646  0.750  1.0
  O  O14  1  0.392  0.355  0.605  1.0
  O  O15  1  0.642  0.037  0.608  1.0
  O  O16  1  0.957  0.601  0.599  1.0
  O  O17  1  0.037  0.642  0.108  1.0
  O  O18  1  0.355  0.392  0.105  1.0
  O  O19  1  0.601  0.957  0.099  1.0
  O  O20  1  0.604  0.641  0.392  1.0
  O  O21  1  0.355  0.958  0.401  1.0
  O  O22  1  0.038  0.393  0.394  1.0
  O  O23  1  0.958  0.355  0.901  1.0
  O  O24  1  0.641  0.604  0.892  1.0
  O  O25  1  0.393  0.038  0.894  1.0
[/CIF]
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