Materials Data on La2Mn17C2 by Materials Project

La2Mn17C2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. La is bonded in a distorted bent 120 degrees geometry to eight Mn and two equivalent C atoms. There are a spread of La–Mn bond distances ranging from 2.99–3.42 Å. Both La–C bond lengths are 2.60 Å. There are seven inequivalent Mn sites. In the first Mn site, Mn is bonded in a 1-coordinate geometry to one La and thirteen Mn atoms. There are a spread of Mn–Mn bond distances ranging from 2.33–2.72 Å. In the second Mn site, Mn is bonded to two equivalent La and ten Mn atoms to form distorted MnLa2Mn10 cuboctahedra that share corners with four MnLa2Mn10 cuboctahedra, corners with four equivalent CLa2Mn4 octahedra, edges with three MnLa2Mn10 cuboctahedra, edges with two equivalent CLa2Mn4 octahedra, and faces with three MnLa2Mn10 cuboctahedra. The corner-sharing octahedra tilt angles range from 20–27°. There are a spread of Mn–Mn bond distances ranging from 2.40–2.78 Å. In the third Mn site, Mn is bonded in a single-bond geometry to six Mn and one C atom. There are a spread of Mn–Mn bond distances ranging from 2.43–2.57 Å. The Mn–C bond length is 1.90 Å. In the fourth Mn site, Mn is bonded in a single-bond geometry to five Mn and one C atom. There are two shorter (2.43 Å) and one longer (2.73 Å) Mn–Mn bond lengths. The Mn–C bond length is 1.90 Å. In the fifth Mn site, Mn is bonded in a 12-coordinate geometry to three equivalent La and nine Mn atoms. Both Mn–Mn bond lengths are 2.47 Å. In the sixth Mn site, Mn is bonded in a 12-coordinate geometry to ten Mn atoms. In the seventh Mn site, Mn is bonded to two equivalent La and ten Mn atoms to form distorted MnLa2Mn10 cuboctahedra that share corners with four MnLa2Mn10 cuboctahedra, corners with two equivalent CLa2Mn4 octahedra, edges with two equivalent MnLa2Mn10 cuboctahedra, faces with four MnLa2Mn10 cuboctahedra, and faces with two equivalent CLa2Mn4 octahedra. The corner-sharing octahedral tilt angles are 49°. C is bonded to two equivalent La and four Mn atoms to form CLa2Mn4 octahedra that share corners with six MnLa2Mn10 cuboctahedra, corners with two equivalent CLa2Mn4 octahedra, edges with two equivalent MnLa2Mn10 cuboctahedra, and faces with two equivalent MnLa2Mn10 cuboctahedra. The corner-sharing octahedral tilt angles are 64°.