Ta3Mo3N4 crystallizes in the tetragonal P4mm space group. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one N(2) and four equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing TaN5 square pyramids. In the second Ta site, Ta(2) is bonded to one N(3) and four equivalent N(1) atoms to form distorted TaN5 square pyramids that share corners with four equivalent Ta(2)N5 square pyramids, edges with four equivalent Ta(2)N5 square pyramids, and edges with four equivalent Mo(3)N5 square pyramids. In the third Ta site, Ta(3) is bonded to one N(4) and four equivalent N(2) atoms to form a mixture of distorted corner and edge-sharing TaN5 square pyramids. There are three inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a linear geometry to one N(2) and one N(3) atom. In the second Mo site, Mo(2) is bonded in a distorted linear geometry to one N(1) and one N(4) atom. In the third Mo site, Mo(3) is bonded to one N(1) and four equivalent N(3) atoms to form MoN5 square pyramids that share corners with four equivalent Mo(3)N5 square pyramids, edges with four equivalent Ta(2)N5 square pyramids, and edges with four equivalent Mo(3)N5 square pyramids. There are four inequivalent N sites. In the first N site, N(1) is bonded to four equivalent Ta(2), one Mo(2), and one Mo(3) atom to form distorted NTa4Mo2 octahedra that share  a cornercorner with one N(4)Ta5Mo octahedra, corners with four equivalent N(1)Ta4Mo2 octahedra, edges with four equivalent N(1)Ta4Mo2 octahedra, and edges with four equivalent N(3)TaMo5 octahedra. The corner-sharing octahedral tilt angles range from 0-20°. In the second N site, N(2) is bonded to one Ta(1), four equivalent Ta(3), and one Mo(1) atom to form NTa5Mo octahedra that share  a cornercorner with one N(3)TaMo5 octahedra, corners with four equivalent N(2)Ta5Mo octahedra, edges with four equivalent N(2)Ta5Mo octahedra, and edges with four equivalent N(4)Ta5Mo octahedra. The corner-sharing octahedral tilt angles range from 0-18°. In the third N site, N(3) is bonded to one Ta(2), one Mo(1), and four equivalent Mo(3) atoms to form NTaMo5 octahedra that share  a cornercorner with one N(2)Ta5Mo octahedra, corners with four equivalent N(3)TaMo5 octahedra, edges with four equivalent N(1)Ta4Mo2 octahedra, and edges with four equivalent N(3)TaMo5 octahedra. The corner-sharing octahedral tilt angles range from 0-18°. In the fourth N site, N(4) is bonded to one Ta(3), four equivalent Ta(1), and one Mo(2) atom to form distorted NTa5Mo octahedra that share  a cornercorner with one N(1)Ta4Mo2 octahedra, corners with four equivalent N(4)Ta5Mo octahedra, edges with four equivalent N(2)Ta5Mo octahedra, and edges with four equivalent N(4)Ta5Mo octahedra. The corner-sharing octahedral tilt angles range from 0-20°.
Ta3Mo3N4 crystallizes in the tetragonal P4mm space group. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one N(2) and four equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing TaN5 square pyramids. The Ta(1)-N(2) bond length is 2.27 Å. All Ta(1)-N(4) bond lengths are 2.19 Å. In the second Ta site, Ta(2) is bonded to one N(3) and four equivalent N(1) atoms to form distorted TaN5 square pyramids that share corners with four equivalent Ta(2)N5 square pyramids, edges with four equivalent Ta(2)N5 square pyramids, and edges with four equivalent Mo(3)N5 square pyramids. The Ta(2)-N(3) bond length is 2.26 Å. All Ta(2)-N(1) bond lengths are 2.19 Å. In the third Ta site, Ta(3) is bonded to one N(4) and four equivalent N(2) atoms to form a mixture of distorted corner and edge-sharing TaN5 square pyramids. The Ta(3)-N(4) bond length is 2.23 Å. All Ta(3)-N(2) bond lengths are 2.18 Å. There are three inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a linear geometry to one N(2) and one N(3) atom. The Mo(1)-N(2) bond length is 2.26 Å. The Mo(1)-N(3) bond length is 2.16 Å. In the second Mo site, Mo(2) is bonded in a distorted linear geometry to one N(1) and one N(4) atom. The Mo(2)-N(1) bond length is 2.24 Å. The Mo(2)-N(4) bond length is 2.24 Å. In the third Mo site, Mo(3) is bonded to one N(1) and four equivalent N(3) atoms to form MoN5 square pyramids that share corners with four equivalent Mo(3)N5 square pyramids, edges with four equivalent Ta(2)N5 square pyramids, and edges with four equivalent Mo(3)N5 square pyramids. The Mo(3)-N(1) bond length is 2.23 Å. All Mo(3)-N(3) bond lengths are 2.18 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded to four equivalent Ta(2), one Mo(2), and one Mo(3) atom to form distorted NTa4Mo2 octahedra that share  a cornercorner with one N(4)Ta5Mo octahedra, corners with four equivalent N(1)Ta4Mo2 octahedra, edges with four equivalent N(1)Ta4Mo2 octahedra, and edges with four equivalent N(3)TaMo5 octahedra. The corner-sharing octahedral tilt angles range from 0-20°. In the second N site, N(2) is bonded to one Ta(1), four equivalent Ta(3), and one Mo(1) atom to form NTa5Mo octahedra that share  a cornercorner with one N(3)TaMo5 octahedra, corners with four equivalent N(2)Ta5Mo octahedra, edges with four equivalent N(2)Ta5Mo octahedra, and edges with four equivalent N(4)Ta5Mo octahedra. The corner-sharing octahedral tilt angles range from 0-18°. In the third N site, N(3) is bonded to one Ta(2), one Mo(1), and four equivalent Mo(3) atoms to form NTaMo5 octahedra that share  a cornercorner with one N(2)Ta5Mo octahedra, corners with four equivalent N(3)TaMo5 octahedra, edges with four equivalent N(1)Ta4Mo2 octahedra, and edges with four equivalent N(3)TaMo5 octahedra. The corner-sharing octahedral tilt angles range from 0-18°. In the fourth N site, N(4) is bonded to one Ta(3), four equivalent Ta(1), and one Mo(2) atom to form distorted NTa5Mo octahedra that share  a cornercorner with one N(1)Ta4Mo2 octahedra, corners with four equivalent N(4)Ta5Mo octahedra, edges with four equivalent N(2)Ta5Mo octahedra, and edges with four equivalent N(4)Ta5Mo octahedra. The corner-sharing octahedral tilt angles range from 0-20°.