ThMn2SiC crystallizes in the orthorhombic Cmcm space group. Th(1) is bonded in a 4-coordinate geometry to three equivalent Si(1) and four equivalent C(1) atoms. Mn(1) is bonded in a distorted single-bond geometry to three equivalent Si(1) and one C(1) atom. Si(1) is bonded in a 9-coordinate geometry to three equivalent Th(1) and six equivalent Mn(1) atoms. C(1) is bonded to four equivalent Th(1) and two equivalent Mn(1) atoms to form a mixture of distorted corner and edge-sharing CTh4Mn2 octahedra. The corner-sharing octahedral tilt angles are 24°.
ThMn2SiC crystallizes in the orthorhombic Cmcm space group. Th(1) is bonded in a 4-coordinate geometry to three equivalent Si(1) and four equivalent C(1) atoms. There is one shorter (3.03 Å) and two longer (3.05 Å) Th(1)-Si(1) bond lengths. All Th(1)-C(1) bond lengths are 2.67 Å. Mn(1) is bonded in a distorted single-bond geometry to three equivalent Si(1) and one C(1) atom. There are two shorter (2.43 Å) and one longer (2.46 Å) Mn(1)-Si(1) bond length. The Mn(1)-C(1) bond length is 1.86 Å. Si(1) is bonded in a 9-coordinate geometry to three equivalent Th(1) and six equivalent Mn(1) atoms. C(1) is bonded to four equivalent Th(1) and two equivalent Mn(1) atoms to form a mixture of distorted corner and edge-sharing CTh4Mn2 octahedra. The corner-sharing octahedral tilt angles are 24°.