The material described by KAlSi2O6 crystallizes in the orthorhombic C222_1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. Al(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(1)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to two equivalent O(2) and two equivalent O(5) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(1)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one K(2), one Al(1), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one K(1), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one K(1), one Al(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one K(2), one Al(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one K(1), one K(2), one Al(1), and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one K(1), one K(2), one Si(1), and one Si(2) atom. is represented by the CIF card [CIF]
data_KAl(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.518
_cell_length_b   7.518
_cell_length_c   10.283
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   91.947
_symmetry_Int_Tables_number   1
_cell_volume   580.851
_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
  K  K0  1  0.296  0.704  0.250  1.0
  K  K1  1  0.704  0.296  0.750  1.0
  K  K2  1  0.204  0.204  0.500  1.0
  K  K3  1  0.796  0.796  0.000  1.0
  Al  Al4  1  0.857  0.358  0.065  1.0
  Al  Al5  1  0.143  0.642  0.565  1.0
  Al  Al6  1  0.642  0.143  0.435  1.0
  Al  Al7  1  0.358  0.857  0.935  1.0
  Si  Si8  1  0.863  0.641  0.315  1.0
  Si  Si9  1  0.137  0.359  0.815  1.0
  Si  Si10  1  0.641  0.863  0.685  1.0
  Si  Si11  1  0.359  0.137  0.185  1.0
  Si  Si12  1  0.944  0.056  0.250  1.0
  Si  Si13  1  0.056  0.944  0.750  1.0
  Si  Si14  1  0.558  0.558  0.500  1.0
  Si  Si15  1  0.442  0.442  0.000  1.0
  O  O16  1  0.864  0.135  0.117  1.0
  O  O17  1  0.136  0.865  0.617  1.0
  O  O18  1  0.654  0.640  0.366  1.0
  O  O19  1  0.346  0.360  0.866  1.0
  O  O20  1  0.865  0.136  0.383  1.0
  O  O21  1  0.135  0.864  0.883  1.0
  O  O22  1  0.640  0.654  0.634  1.0
  O  O23  1  0.360  0.346  0.134  1.0
  O  O24  1  0.005  0.394  0.934  1.0
  O  O25  1  0.995  0.606  0.434  1.0
  O  O26  1  0.891  0.507  0.193  1.0
  O  O27  1  0.109  0.493  0.693  1.0
  O  O28  1  0.606  0.995  0.566  1.0
  O  O29  1  0.394  0.005  0.066  1.0
  O  O30  1  0.507  0.891  0.807  1.0
  O  O31  1  0.493  0.109  0.307  1.0
  O  O32  1  0.653  0.407  0.989  1.0
  O  O33  1  0.347  0.593  0.489  1.0
  O  O34  1  0.909  0.838  0.247  1.0
  O  O35  1  0.091  0.162  0.747  1.0
  O  O36  1  0.593  0.347  0.511  1.0
  O  O37  1  0.407  0.653  0.011  1.0
  O  O38  1  0.838  0.909  0.753  1.0
  O  O39  1  0.162  0.091  0.253  1.0
[/CIF]
.
The material described by KAlSi2O6 crystallizes in the orthorhombic C222_1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. Al(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(1)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to two equivalent O(2) and two equivalent O(5) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(1)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one K(2), one Al(1), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one K(1), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one K(1), one Al(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one K(2), one Al(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one K(1), one K(2), one Al(1), and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one K(1), one K(2), one Si(1), and one Si(2) atom. is represented by the CIF card [CIF]
data_KAl(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.518
_cell_length_b   7.518
_cell_length_c   10.283
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   91.947
_symmetry_Int_Tables_number   1
_cell_volume   580.851
_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
  K  K0  1  0.296  0.704  0.250  1.0
  K  K1  1  0.704  0.296  0.750  1.0
  K  K2  1  0.204  0.204  0.500  1.0
  K  K3  1  0.796  0.796  0.000  1.0
  Al  Al4  1  0.857  0.358  0.065  1.0
  Al  Al5  1  0.143  0.642  0.565  1.0
  Al  Al6  1  0.642  0.143  0.435  1.0
  Al  Al7  1  0.358  0.857  0.935  1.0
  Si  Si8  1  0.863  0.641  0.315  1.0
  Si  Si9  1  0.137  0.359  0.815  1.0
  Si  Si10  1  0.641  0.863  0.685  1.0
  Si  Si11  1  0.359  0.137  0.185  1.0
  Si  Si12  1  0.944  0.056  0.250  1.0
  Si  Si13  1  0.056  0.944  0.750  1.0
  Si  Si14  1  0.558  0.558  0.500  1.0
  Si  Si15  1  0.442  0.442  0.000  1.0
  O  O16  1  0.864  0.135  0.117  1.0
  O  O17  1  0.136  0.865  0.617  1.0
  O  O18  1  0.654  0.640  0.366  1.0
  O  O19  1  0.346  0.360  0.866  1.0
  O  O20  1  0.865  0.136  0.383  1.0
  O  O21  1  0.135  0.864  0.883  1.0
  O  O22  1  0.640  0.654  0.634  1.0
  O  O23  1  0.360  0.346  0.134  1.0
  O  O24  1  0.005  0.394  0.934  1.0
  O  O25  1  0.995  0.606  0.434  1.0
  O  O26  1  0.891  0.507  0.193  1.0
  O  O27  1  0.109  0.493  0.693  1.0
  O  O28  1  0.606  0.995  0.566  1.0
  O  O29  1  0.394  0.005  0.066  1.0
  O  O30  1  0.507  0.891  0.807  1.0
  O  O31  1  0.493  0.109  0.307  1.0
  O  O32  1  0.653  0.407  0.989  1.0
  O  O33  1  0.347  0.593  0.489  1.0
  O  O34  1  0.909  0.838  0.247  1.0
  O  O35  1  0.091  0.162  0.747  1.0
  O  O36  1  0.593  0.347  0.511  1.0
  O  O37  1  0.407  0.653  0.011  1.0
  O  O38  1  0.838  0.909  0.753  1.0
  O  O39  1  0.162  0.091  0.253  1.0
[/CIF]
.