ZrNb3C4 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. Zr(1) is bonded to six equivalent C(1) atoms to form ZrC6 octahedra that share corners with six equivalent Nb(1)C6 octahedra, edges with six equivalent Zr(1)C6 octahedra, and edges with six equivalent Nb(1)C6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to three equivalent C(1) and three equivalent C(2) atoms to form NbC6 octahedra that share corners with three equivalent Zr(1)C6 octahedra, corners with three equivalent Nb(2)C6 octahedra, edges with three equivalent Zr(1)C6 octahedra, edges with three equivalent Nb(2)C6 octahedra, and edges with six equivalent Nb(1)C6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second Nb site, Nb(2) is bonded to six equivalent C(2) atoms to form a mixture of corner and edge-sharing NbC6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent C sites. In the first C site, C(1) is bonded to three equivalent Zr(1) and three equivalent Nb(1) atoms to form CZr3Nb3 octahedra that share corners with three equivalent C(2)Nb6 octahedra, corners with three equivalent C(1)Zr3Nb3 octahedra, edges with three equivalent C(2)Nb6 octahedra, and edges with nine equivalent C(1)Zr3Nb3 octahedra. The corner-sharing octahedra are not tilted. In the second C site, C(2) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form CNb6 octahedra that share corners with three equivalent C(2)Nb6 octahedra, corners with three equivalent C(1)Zr3Nb3 octahedra, edges with three equivalent C(1)Zr3Nb3 octahedra, and edges with nine equivalent C(2)Nb6 octahedra. The corner-sharing octahedra are not tilted.
ZrNb3C4 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. Zr(1) is bonded to six equivalent C(1) atoms to form ZrC6 octahedra that share corners with six equivalent Nb(1)C6 octahedra, edges with six equivalent Zr(1)C6 octahedra, and edges with six equivalent Nb(1)C6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Zr(1)-C(1) bond lengths are 2.33 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to three equivalent C(1) and three equivalent C(2) atoms to form NbC6 octahedra that share corners with three equivalent Zr(1)C6 octahedra, corners with three equivalent Nb(2)C6 octahedra, edges with three equivalent Zr(1)C6 octahedra, edges with three equivalent Nb(2)C6 octahedra, and edges with six equivalent Nb(1)C6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. All Nb(1)-C(1) bond lengths are 2.26 Å. All Nb(1)-C(2) bond lengths are 2.26 Å. In the second Nb site, Nb(2) is bonded to six equivalent C(2) atoms to form a mixture of corner and edge-sharing NbC6 octahedra. The corner-sharing octahedra are not tilted. All Nb(2)-C(2) bond lengths are 2.26 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded to three equivalent Zr(1) and three equivalent Nb(1) atoms to form CZr3Nb3 octahedra that share corners with three equivalent C(2)Nb6 octahedra, corners with three equivalent C(1)Zr3Nb3 octahedra, edges with three equivalent C(2)Nb6 octahedra, and edges with nine equivalent C(1)Zr3Nb3 octahedra. The corner-sharing octahedra are not tilted. In the second C site, C(2) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form CNb6 octahedra that share corners with three equivalent C(2)Nb6 octahedra, corners with three equivalent C(1)Zr3Nb3 octahedra, edges with three equivalent C(1)Zr3Nb3 octahedra, and edges with nine equivalent C(2)Nb6 octahedra. The corner-sharing octahedra are not tilted.