The compound described by Li2Ta3N5 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one N(5), two equivalent N(1), and three equivalent N(2) atoms to form LiN6 octahedra that share  a cornercorner with one Li(2)N6 octahedra,  a cornercorner with one Ta(1)N6 octahedra,  a cornercorner with one Ta(2)N6 octahedra,  a cornercorner with one Ta(3)N6 octahedra, corners with two equivalent Li(1)N6 octahedra,  an edgeedge with one Li(2)N6 octahedra, edges with three equivalent Li(1)N6 octahedra, edges with three equivalent Ta(2)N6 octahedra, and edges with five equivalent Ta(1)N6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second Li site, Li(2) is bonded to one N(1), one N(5), two equivalent N(3), and two equivalent N(4) atoms to form LiN6 octahedra that share  a cornercorner with one Li(1)N6 octahedra,  a cornercorner with one Ta(1)N6 octahedra,  a cornercorner with one Ta(2)N6 octahedra,  a cornercorner with one Ta(3)N6 octahedra, corners with two equivalent Li(2)N6 octahedra,  an edgeedge with one Li(1)N6 octahedra,  an edgeedge with one Li(2)N6 octahedra, edges with two equivalent Ta(1)N6 octahedra, edges with three equivalent Ta(2)N6 octahedra, and edges with five equivalent Ta(3)N6 octahedra. The corner-sharing octahedral tilt angles range from 1-9°. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one N(3), one N(5), two equivalent N(1), and two equivalent N(2) atoms to form TaN6 octahedra that share  a cornercorner with one Li(1)N6 octahedra,  a cornercorner with one Li(2)N6 octahedra,  a cornercorner with one Ta(2)N6 octahedra,  a cornercorner with one Ta(3)N6 octahedra, corners with two equivalent Ta(1)N6 octahedra,  an edgeedge with one Ta(1)N6 octahedra,  an edgeedge with one Ta(3)N6 octahedra, edges with two equivalent Li(2)N6 octahedra, edges with three equivalent Ta(2)N6 octahedra, and edges with five equivalent Li(1)N6 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the second Ta site, Ta(2) is bonded to one N(1), one N(2), one N(3), one N(4), and two equivalent N(5) atoms to form TaN6 octahedra that share  a cornercorner with one Li(1)N6 octahedra,  a cornercorner with one Li(2)N6 octahedra,  a cornercorner with one Ta(1)N6 octahedra,  a cornercorner with one Ta(3)N6 octahedra, corners with two equivalent Ta(2)N6 octahedra, edges with three equivalent Li(1)N6 octahedra, edges with three equivalent Li(2)N6 octahedra, edges with three equivalent Ta(1)N6 octahedra, and edges with three equivalent Ta(3)N6 octahedra. The corner-sharing octahedral tilt angles range from 1-7°. In the third Ta site, Ta(3) is bonded to one N(5), two equivalent N(3), and three equivalent N(4) atoms to form TaN6 octahedra that share  a cornercorner with one Li(1)N6 octahedra,  a cornercorner with one Li(2)N6 octahedra,  a cornercorner with one Ta(1)N6 octahedra,  a cornercorner with one Ta(2)N6 octahedra, corners with two equivalent Ta(3)N6 octahedra,  an edgeedge with one Ta(1)N6 octahedra, edges with three equivalent Ta(2)N6 octahedra, edges with three equivalent Ta(3)N6 octahedra, and edges with five equivalent Li(2)N6 octahedra. The corner-sharing octahedral tilt angles range from 1-7°. There are five inequivalent N sites. In the first N site, N(1) is bonded to one Li(2), two equivalent Li(1), one Ta(2), and two equivalent Ta(1) atoms to form NLi3Ta3 octahedra that share  a cornercorner with one N(3)Li2Ta4 octahedra,  a cornercorner with one N(4)Li2Ta4 octahedra,  a cornercorner with one N(5)Li2Ta4 octahedra,  a cornercorner with one N(2)Li3Ta3 octahedra, corners with two equivalent N(1)Li3Ta3 octahedra,  an edgeedge with one N(4)Li2Ta4 octahedra,  an edgeedge with one N(1)Li3Ta3 octahedra, edges with two equivalent N(3)Li2Ta4 octahedra, edges with three equivalent N(5)Li2Ta4 octahedra, and edges with five equivalent N(2)Li3Ta3 octahedra. The corner-sharing octahedral tilt angles range from 1-10°. In the second N site, N(2) is bonded to three equivalent Li(1), one Ta(2), and two equivalent Ta(1) atoms to form NLi3Ta3 octahedra that share  a cornercorner with one N(3)Li2Ta4 octahedra,  a cornercorner with one N(4)Li2Ta4 octahedra,  a cornercorner with one N(5)Li2Ta4 octahedra,  a cornercorner with one N(1)Li3Ta3 octahedra, corners with two equivalent N(2)Li3Ta3 octahedra,  an edgeedge with one N(3)Li2Ta4 octahedra, edges with three equivalent N(5)Li2Ta4 octahedra, edges with three equivalent N(2)Li3Ta3 octahedra, and edges with five equivalent N(1)Li3Ta3 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. In the third N site, N(3) is bonded to two equivalent Li(2), one Ta(1), one Ta(2), and two equivalent Ta(3) atoms to form NLi2Ta4 octahedra that share  a cornercorner with one N(4)Li2Ta4 octahedra,  a cornercorner with one N(5)Li2Ta4 octahedra,  a cornercorner with one N(1)Li3Ta3 octahedra,  a cornercorner with one N(2)Li3Ta3 octahedra, corners with two equivalent N(3)Li2Ta4 octahedra,  an edgeedge with one N(3)Li2Ta4 octahedra,  an edgeedge with one N(2)Li3Ta3 octahedra, edges with two equivalent N(1)Li3Ta3 octahedra, edges with three equivalent N(5)Li2Ta4 octahedra, and edges with five equivalent N(4)Li2Ta4 octahedra. The corner-sharing octahedral tilt angles range from 2-4°. In the fourth N site, N(4) is bonded to two equivalent Li(2), one Ta(2), and three equivalent Ta(3) atoms to form NLi2Ta4 octahedra that share  a cornercorner with one N(3)Li2Ta4 octahedra,  a cornercorner with one N(5)Li2Ta4 octahedra,  a cornercorner with one N(1)Li3Ta3 octahedra,  a cornercorner with one N(2)Li3Ta3 octahedra, corners with two equivalent N(4)Li2Ta4 octahedra,  an edgeedge with one N(1)Li3Ta3 octahedra, edges with three equivalent N(4)Li2Ta4 octahedra, edges with three equivalent N(5)Li2Ta4 octahedra, and edges with five equivalent N(3)Li2Ta4 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. In the fifth N site, N(5) is bonded to one Li(1), one Li(2), one Ta(1), one Ta(3), and two equivalent Ta(2) atoms to form NLi2Ta4 octahedra that share  a cornercorner with one N(3)Li2Ta4 octahedra,  a cornercorner with one N(4)Li2Ta4 octahedra,  a cornercorner with one N(1)Li3Ta3 octahedra,  a cornercorner with one N(2)Li3Ta3 octahedra, corners with two equivalent N(5)Li2Ta4 octahedra, edges with three equivalent N(3)Li2Ta4 octahedra, edges with three equivalent N(4)Li2Ta4 octahedra, edges with three equivalent N(1)Li3Ta3 octahedra, and edges with three equivalent N(2)Li3Ta3 octahedra. The corner-sharing octahedral tilt angles range from 2-7°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Ta3N5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.341
_cell_length_b   5.341
_cell_length_c   9.640
_cell_angle_alpha   89.065
_cell_angle_beta   89.065
_cell_angle_gamma   46.328
_symmetry_Int_Tables_number   1
_cell_volume   198.869
_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
  Li  Li0  1  0.647  0.647  0.452  1.0
  Li  Li1  1  0.457  0.457  0.847  1.0
  Li  Li2  1  0.543  0.543  0.153  1.0
  Li  Li3  1  0.353  0.353  0.548  1.0
  Ta  Ta4  1  0.055  0.055  0.644  1.0
  Ta  Ta5  1  0.945  0.945  0.356  1.0
  Ta  Ta6  1  0.763  0.763  0.744  1.0
  Ta  Ta7  1  0.237  0.237  0.256  1.0
  Ta  Ta8  1  0.142  0.142  0.953  1.0
  Ta  Ta9  1  0.858  0.858  0.047  1.0
  N  N10  1  0.568  0.568  0.656  1.0
  N  N11  1  0.432  0.432  0.344  1.0
  N  N12  1  0.861  0.861  0.554  1.0
  N  N13  1  0.046  0.046  0.154  1.0
  N  N14  1  0.954  0.954  0.846  1.0
  N  N15  1  0.139  0.139  0.446  1.0
  N  N16  1  0.346  0.346  0.050  1.0
  N  N17  1  0.654  0.654  0.950  1.0
  N  N18  1  0.750  0.750  0.251  1.0
  N  N19  1  0.250  0.250  0.749  1.0
[/CIF]
.
The compound described by Li2Ta3N5 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one N(5), two equivalent N(1), and three equivalent N(2) atoms to form LiN6 octahedra that share  a cornercorner with one Li(2)N6 octahedra,  a cornercorner with one Ta(1)N6 octahedra,  a cornercorner with one Ta(2)N6 octahedra,  a cornercorner with one Ta(3)N6 octahedra, corners with two equivalent Li(1)N6 octahedra,  an edgeedge with one Li(2)N6 octahedra, edges with three equivalent Li(1)N6 octahedra, edges with three equivalent Ta(2)N6 octahedra, and edges with five equivalent Ta(1)N6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second Li site, Li(2) is bonded to one N(1), one N(5), two equivalent N(3), and two equivalent N(4) atoms to form LiN6 octahedra that share  a cornercorner with one Li(1)N6 octahedra,  a cornercorner with one Ta(1)N6 octahedra,  a cornercorner with one Ta(2)N6 octahedra,  a cornercorner with one Ta(3)N6 octahedra, corners with two equivalent Li(2)N6 octahedra,  an edgeedge with one Li(1)N6 octahedra,  an edgeedge with one Li(2)N6 octahedra, edges with two equivalent Ta(1)N6 octahedra, edges with three equivalent Ta(2)N6 octahedra, and edges with five equivalent Ta(3)N6 octahedra. The corner-sharing octahedral tilt angles range from 1-9°. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one N(3), one N(5), two equivalent N(1), and two equivalent N(2) atoms to form TaN6 octahedra that share  a cornercorner with one Li(1)N6 octahedra,  a cornercorner with one Li(2)N6 octahedra,  a cornercorner with one Ta(2)N6 octahedra,  a cornercorner with one Ta(3)N6 octahedra, corners with two equivalent Ta(1)N6 octahedra,  an edgeedge with one Ta(1)N6 octahedra,  an edgeedge with one Ta(3)N6 octahedra, edges with two equivalent Li(2)N6 octahedra, edges with three equivalent Ta(2)N6 octahedra, and edges with five equivalent Li(1)N6 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the second Ta site, Ta(2) is bonded to one N(1), one N(2), one N(3), one N(4), and two equivalent N(5) atoms to form TaN6 octahedra that share  a cornercorner with one Li(1)N6 octahedra,  a cornercorner with one Li(2)N6 octahedra,  a cornercorner with one Ta(1)N6 octahedra,  a cornercorner with one Ta(3)N6 octahedra, corners with two equivalent Ta(2)N6 octahedra, edges with three equivalent Li(1)N6 octahedra, edges with three equivalent Li(2)N6 octahedra, edges with three equivalent Ta(1)N6 octahedra, and edges with three equivalent Ta(3)N6 octahedra. The corner-sharing octahedral tilt angles range from 1-7°. In the third Ta site, Ta(3) is bonded to one N(5), two equivalent N(3), and three equivalent N(4) atoms to form TaN6 octahedra that share  a cornercorner with one Li(1)N6 octahedra,  a cornercorner with one Li(2)N6 octahedra,  a cornercorner with one Ta(1)N6 octahedra,  a cornercorner with one Ta(2)N6 octahedra, corners with two equivalent Ta(3)N6 octahedra,  an edgeedge with one Ta(1)N6 octahedra, edges with three equivalent Ta(2)N6 octahedra, edges with three equivalent Ta(3)N6 octahedra, and edges with five equivalent Li(2)N6 octahedra. The corner-sharing octahedral tilt angles range from 1-7°. There are five inequivalent N sites. In the first N site, N(1) is bonded to one Li(2), two equivalent Li(1), one Ta(2), and two equivalent Ta(1) atoms to form NLi3Ta3 octahedra that share  a cornercorner with one N(3)Li2Ta4 octahedra,  a cornercorner with one N(4)Li2Ta4 octahedra,  a cornercorner with one N(5)Li2Ta4 octahedra,  a cornercorner with one N(2)Li3Ta3 octahedra, corners with two equivalent N(1)Li3Ta3 octahedra,  an edgeedge with one N(4)Li2Ta4 octahedra,  an edgeedge with one N(1)Li3Ta3 octahedra, edges with two equivalent N(3)Li2Ta4 octahedra, edges with three equivalent N(5)Li2Ta4 octahedra, and edges with five equivalent N(2)Li3Ta3 octahedra. The corner-sharing octahedral tilt angles range from 1-10°. In the second N site, N(2) is bonded to three equivalent Li(1), one Ta(2), and two equivalent Ta(1) atoms to form NLi3Ta3 octahedra that share  a cornercorner with one N(3)Li2Ta4 octahedra,  a cornercorner with one N(4)Li2Ta4 octahedra,  a cornercorner with one N(5)Li2Ta4 octahedra,  a cornercorner with one N(1)Li3Ta3 octahedra, corners with two equivalent N(2)Li3Ta3 octahedra,  an edgeedge with one N(3)Li2Ta4 octahedra, edges with three equivalent N(5)Li2Ta4 octahedra, edges with three equivalent N(2)Li3Ta3 octahedra, and edges with five equivalent N(1)Li3Ta3 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. In the third N site, N(3) is bonded to two equivalent Li(2), one Ta(1), one Ta(2), and two equivalent Ta(3) atoms to form NLi2Ta4 octahedra that share  a cornercorner with one N(4)Li2Ta4 octahedra,  a cornercorner with one N(5)Li2Ta4 octahedra,  a cornercorner with one N(1)Li3Ta3 octahedra,  a cornercorner with one N(2)Li3Ta3 octahedra, corners with two equivalent N(3)Li2Ta4 octahedra,  an edgeedge with one N(3)Li2Ta4 octahedra,  an edgeedge with one N(2)Li3Ta3 octahedra, edges with two equivalent N(1)Li3Ta3 octahedra, edges with three equivalent N(5)Li2Ta4 octahedra, and edges with five equivalent N(4)Li2Ta4 octahedra. The corner-sharing octahedral tilt angles range from 2-4°. In the fourth N site, N(4) is bonded to two equivalent Li(2), one Ta(2), and three equivalent Ta(3) atoms to form NLi2Ta4 octahedra that share  a cornercorner with one N(3)Li2Ta4 octahedra,  a cornercorner with one N(5)Li2Ta4 octahedra,  a cornercorner with one N(1)Li3Ta3 octahedra,  a cornercorner with one N(2)Li3Ta3 octahedra, corners with two equivalent N(4)Li2Ta4 octahedra,  an edgeedge with one N(1)Li3Ta3 octahedra, edges with three equivalent N(4)Li2Ta4 octahedra, edges with three equivalent N(5)Li2Ta4 octahedra, and edges with five equivalent N(3)Li2Ta4 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. In the fifth N site, N(5) is bonded to one Li(1), one Li(2), one Ta(1), one Ta(3), and two equivalent Ta(2) atoms to form NLi2Ta4 octahedra that share  a cornercorner with one N(3)Li2Ta4 octahedra,  a cornercorner with one N(4)Li2Ta4 octahedra,  a cornercorner with one N(1)Li3Ta3 octahedra,  a cornercorner with one N(2)Li3Ta3 octahedra, corners with two equivalent N(5)Li2Ta4 octahedra, edges with three equivalent N(3)Li2Ta4 octahedra, edges with three equivalent N(4)Li2Ta4 octahedra, edges with three equivalent N(1)Li3Ta3 octahedra, and edges with three equivalent N(2)Li3Ta3 octahedra. The corner-sharing octahedral tilt angles range from 2-7°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2Ta3N5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.341
_cell_length_b   5.341
_cell_length_c   9.640
_cell_angle_alpha   89.065
_cell_angle_beta   89.065
_cell_angle_gamma   46.328
_symmetry_Int_Tables_number   1
_cell_volume   198.869
_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
  Li  Li0  1  0.647  0.647  0.452  1.0
  Li  Li1  1  0.457  0.457  0.847  1.0
  Li  Li2  1  0.543  0.543  0.153  1.0
  Li  Li3  1  0.353  0.353  0.548  1.0
  Ta  Ta4  1  0.055  0.055  0.644  1.0
  Ta  Ta5  1  0.945  0.945  0.356  1.0
  Ta  Ta6  1  0.763  0.763  0.744  1.0
  Ta  Ta7  1  0.237  0.237  0.256  1.0
  Ta  Ta8  1  0.142  0.142  0.953  1.0
  Ta  Ta9  1  0.858  0.858  0.047  1.0
  N  N10  1  0.568  0.568  0.656  1.0
  N  N11  1  0.432  0.432  0.344  1.0
  N  N12  1  0.861  0.861  0.554  1.0
  N  N13  1  0.046  0.046  0.154  1.0
  N  N14  1  0.954  0.954  0.846  1.0
  N  N15  1  0.139  0.139  0.446  1.0
  N  N16  1  0.346  0.346  0.050  1.0
  N  N17  1  0.654  0.654  0.950  1.0
  N  N18  1  0.750  0.750  0.251  1.0
  N  N19  1  0.250  0.250  0.749  1.0
[/CIF]
.