The material described by Ti12AlSi3C8 is MAX Phase-derived structured and crystallizes in the trigonal P-3m1 space group. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to six equivalent C(1) atoms to form edge-sharing TiC6 octahedra. In the second Ti site, Ti(2) is bonded to two equivalent C(2) and four equivalent C(1) atoms to form edge-sharing TiC6 octahedra. In the third Ti site, Ti(3) is bonded in a 3-coordinate geometry to one Al(1), two equivalent Si(1), one C(2), and two equivalent C(1) atoms. In the fourth Ti site, Ti(4) is bonded in a 3-coordinate geometry to three equivalent Si(1) and three equivalent C(1) atoms. Al(1) is bonded to six equivalent Ti(3) atoms to form distorted AlTi6 cuboctahedra that share corners with six equivalent C(2)Ti6 octahedra and edges with six equivalent C(1)Ti6 octahedra. The corner-sharing octahedral tilt angles are 17°. Si(1) is bonded in a 6-coordinate geometry to two equivalent Ti(4) and four equivalent Ti(3) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to one Ti(1), one Ti(4), two equivalent Ti(2), and two equivalent Ti(3) atoms to form CTi6 octahedra that share corners with three equivalent C(1)Ti6 octahedra,  an edgeedge with one Al(1)Ti6 cuboctahedra, edges with three equivalent C(2)Ti6 octahedra, and edges with six equivalent C(1)Ti6 octahedra. The corner-sharing octahedra are not tilted. In the second C site, C(2) is bonded to three equivalent Ti(2) and three equivalent Ti(3) atoms to form CTi6 octahedra that share corners with three equivalent Al(1)Ti6 cuboctahedra, corners with three equivalent C(2)Ti6 octahedra, and edges with nine equivalent C(1)Ti6 octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF card [CIF]
data_Ti12AlSi3C8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.160
_cell_length_b   6.160
_cell_length_c   17.912
_cell_angle_alpha   89.990
_cell_angle_beta   90.002
_cell_angle_gamma   119.992
_symmetry_Int_Tables_number   1
_cell_volume   588.603
_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
  Ti  Ti0  1  0.000  0.000  0.000  1.0
  Ti  Ti1  1  0.001  0.500  0.000  1.0
  Ti  Ti2  1  0.501  0.500  1.000  1.0
  Ti  Ti3  1  0.501  0.000  0.000  1.0
  Ti  Ti4  1  0.000  0.000  0.500  1.0
  Ti  Ti5  1  0.000  0.500  0.500  1.0
  Ti  Ti6  1  0.501  0.500  0.500  1.0
  Ti  Ti7  1  0.501  0.000  0.500  1.0
  Ti  Ti8  1  0.664  0.832  0.868  1.0
  Ti  Ti9  1  0.667  0.334  0.864  1.0
  Ti  Ti10  1  0.168  0.336  0.868  1.0
  Ti  Ti11  1  0.168  0.832  0.868  1.0
  Ti  Ti12  1  0.832  0.168  0.133  1.0
  Ti  Ti13  1  0.334  0.667  0.136  1.0
  Ti  Ti14  1  0.832  0.664  0.133  1.0
  Ti  Ti15  1  0.337  0.168  0.132  1.0
  Ti  Ti16  1  0.664  0.832  0.633  1.0
  Ti  Ti17  1  0.667  0.333  0.636  1.0
  Ti  Ti18  1  0.168  0.336  0.632  1.0
  Ti  Ti19  1  0.168  0.832  0.632  1.0
  Ti  Ti20  1  0.832  0.168  0.367  1.0
  Ti  Ti21  1  0.334  0.667  0.364  1.0
  Ti  Ti22  1  0.832  0.664  0.367  1.0
  Ti  Ti23  1  0.336  0.168  0.367  1.0
  Al  Al24  1  0.001  1.000  0.750  1.0
  Al  Al25  1  0.001  0.000  0.250  1.0
  Si  Si26  1  0.011  0.506  0.750  1.0
  Si  Si27  1  0.495  0.506  0.750  1.0
  Si  Si28  1  0.495  0.989  0.750  1.0
  Si  Si29  1  0.990  0.494  0.250  1.0
  Si  Si30  1  0.506  0.494  0.250  1.0
  Si  Si31  1  0.506  0.011  0.250  1.0
  C  C32  1  0.666  0.833  0.428  1.0
  C  C33  1  0.667  0.333  0.429  1.0
  C  C34  1  0.167  0.334  0.428  1.0
  C  C35  1  0.167  0.833  0.428  1.0
  C  C36  1  0.833  0.167  0.572  1.0
  C  C37  1  0.334  0.667  0.571  1.0
  C  C38  1  0.833  0.666  0.572  1.0
  C  C39  1  0.335  0.167  0.572  1.0
  C  C40  1  0.666  0.833  0.072  1.0
  C  C41  1  0.667  0.333  0.071  1.0
  C  C42  1  0.167  0.334  0.072  1.0
  C  C43  1  0.167  0.833  0.072  1.0
  C  C44  1  0.833  0.167  0.928  1.0
  C  C45  1  0.334  0.667  0.929  1.0
  C  C46  1  0.833  0.666  0.928  1.0
  C  C47  1  0.335  0.167  0.928  1.0
[/CIF]
.
The material described by Ti12AlSi3C8 is MAX Phase-derived structured and crystallizes in the trigonal P-3m1 space group. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to six equivalent C(1) atoms to form edge-sharing TiC6 octahedra. In the second Ti site, Ti(2) is bonded to two equivalent C(2) and four equivalent C(1) atoms to form edge-sharing TiC6 octahedra. In the third Ti site, Ti(3) is bonded in a 3-coordinate geometry to one Al(1), two equivalent Si(1), one C(2), and two equivalent C(1) atoms. In the fourth Ti site, Ti(4) is bonded in a 3-coordinate geometry to three equivalent Si(1) and three equivalent C(1) atoms. Al(1) is bonded to six equivalent Ti(3) atoms to form distorted AlTi6 cuboctahedra that share corners with six equivalent C(2)Ti6 octahedra and edges with six equivalent C(1)Ti6 octahedra. The corner-sharing octahedral tilt angles are 17°. Si(1) is bonded in a 6-coordinate geometry to two equivalent Ti(4) and four equivalent Ti(3) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to one Ti(1), one Ti(4), two equivalent Ti(2), and two equivalent Ti(3) atoms to form CTi6 octahedra that share corners with three equivalent C(1)Ti6 octahedra,  an edgeedge with one Al(1)Ti6 cuboctahedra, edges with three equivalent C(2)Ti6 octahedra, and edges with six equivalent C(1)Ti6 octahedra. The corner-sharing octahedra are not tilted. In the second C site, C(2) is bonded to three equivalent Ti(2) and three equivalent Ti(3) atoms to form CTi6 octahedra that share corners with three equivalent Al(1)Ti6 cuboctahedra, corners with three equivalent C(2)Ti6 octahedra, and edges with nine equivalent C(1)Ti6 octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF card [CIF]
data_Ti12AlSi3C8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.160
_cell_length_b   6.160
_cell_length_c   17.912
_cell_angle_alpha   89.990
_cell_angle_beta   90.002
_cell_angle_gamma   119.992
_symmetry_Int_Tables_number   1
_cell_volume   588.603
_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
  Ti  Ti0  1  0.000  0.000  0.000  1.0
  Ti  Ti1  1  0.001  0.500  0.000  1.0
  Ti  Ti2  1  0.501  0.500  1.000  1.0
  Ti  Ti3  1  0.501  0.000  0.000  1.0
  Ti  Ti4  1  0.000  0.000  0.500  1.0
  Ti  Ti5  1  0.000  0.500  0.500  1.0
  Ti  Ti6  1  0.501  0.500  0.500  1.0
  Ti  Ti7  1  0.501  0.000  0.500  1.0
  Ti  Ti8  1  0.664  0.832  0.868  1.0
  Ti  Ti9  1  0.667  0.334  0.864  1.0
  Ti  Ti10  1  0.168  0.336  0.868  1.0
  Ti  Ti11  1  0.168  0.832  0.868  1.0
  Ti  Ti12  1  0.832  0.168  0.133  1.0
  Ti  Ti13  1  0.334  0.667  0.136  1.0
  Ti  Ti14  1  0.832  0.664  0.133  1.0
  Ti  Ti15  1  0.337  0.168  0.132  1.0
  Ti  Ti16  1  0.664  0.832  0.633  1.0
  Ti  Ti17  1  0.667  0.333  0.636  1.0
  Ti  Ti18  1  0.168  0.336  0.632  1.0
  Ti  Ti19  1  0.168  0.832  0.632  1.0
  Ti  Ti20  1  0.832  0.168  0.367  1.0
  Ti  Ti21  1  0.334  0.667  0.364  1.0
  Ti  Ti22  1  0.832  0.664  0.367  1.0
  Ti  Ti23  1  0.336  0.168  0.367  1.0
  Al  Al24  1  0.001  1.000  0.750  1.0
  Al  Al25  1  0.001  0.000  0.250  1.0
  Si  Si26  1  0.011  0.506  0.750  1.0
  Si  Si27  1  0.495  0.506  0.750  1.0
  Si  Si28  1  0.495  0.989  0.750  1.0
  Si  Si29  1  0.990  0.494  0.250  1.0
  Si  Si30  1  0.506  0.494  0.250  1.0
  Si  Si31  1  0.506  0.011  0.250  1.0
  C  C32  1  0.666  0.833  0.428  1.0
  C  C33  1  0.667  0.333  0.429  1.0
  C  C34  1  0.167  0.334  0.428  1.0
  C  C35  1  0.167  0.833  0.428  1.0
  C  C36  1  0.833  0.167  0.572  1.0
  C  C37  1  0.334  0.667  0.571  1.0
  C  C38  1  0.833  0.666  0.572  1.0
  C  C39  1  0.335  0.167  0.572  1.0
  C  C40  1  0.666  0.833  0.072  1.0
  C  C41  1  0.667  0.333  0.071  1.0
  C  C42  1  0.167  0.334  0.072  1.0
  C  C43  1  0.167  0.833  0.072  1.0
  C  C44  1  0.833  0.167  0.928  1.0
  C  C45  1  0.334  0.667  0.929  1.0
  C  C46  1  0.833  0.666  0.928  1.0
  C  C47  1  0.335  0.167  0.928  1.0
[/CIF]
.