Nb2C is zeta iron carbide-like structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 3-coordinate geometry to three equivalent C(1) atoms. In the second Nb site, Nb(2) is bonded in a 3-coordinate geometry to three equivalent C(1) atoms. C(1) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 50°.
Nb2C is zeta iron carbide-like structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 3-coordinate geometry to three equivalent C(1) atoms. There are two shorter (2.19 Å) and one longer (2.26 Å) Nb(1)-C(1) bond length. In the second Nb site, Nb(2) is bonded in a 3-coordinate geometry to three equivalent C(1) atoms. There are two shorter (2.19 Å) and one longer (2.22 Å) Nb(2)-C(1) bond length. C(1) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 50°.