Materials Data on Sm2Co18Si4C3 by Materials Project
Sm2Co18Si4C3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Sm3+ is bonded in a T-shaped geometry to three C4- atoms. There are two shorter (2.60 Å) and one longer (2.63 Å) Sm–C bond lengths. There are five inequivalent Co+1.22+ sites. In the first Co+1.22+ site, Co+1.22+ is bonded in a single-bond geometry to two Si4- and one C4- atom. There are one shorter (2.35 Å) and one longer (2.38 Å) Co–Si bond lengths. The Co–C bond length is 1.83 Å. In the second Co+1.22+ site, Co+1.22+ is bonded in a single-bond geometry to two Si4- and one C4- atom. There are one shorter (2.36 Å) and one longer (2.37 Å) Co–Si bond lengths. The Co–C bond length is 1.83 Å. In the third Co+1.22+ site, Co+1.22+ is bonded in a water-like geometry to two Si4- atoms. There are one shorter (2.37 Å) and one longer (2.42 Å) Co–Si bond lengths. In the fourth Co+1.22+ site, Co+1.22+ is bonded in a single-bond geometry to two Si4- and one C4- atom. There are one shorter (2.34 Å) and one longer (2.41 Å) Co–Si bond lengths. The Co–C bond length is 1.83 Å. In the fifth Co+1.22+ site, Co+1.22+ is bonded to four Si4- atoms to form distorted corner-sharing CoSi4 trigonal pyramids. There are a spread of Co–Si bond distances ranging from 2.58–2.62 Å. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 12-coordinate geometry to ten Co+1.22+ atoms. In the second Si4- site, Si4- is bonded in a 10-coordinate geometry to ten Co+1.22+ atoms. In the third Si4- site, Si4- is bonded in a 10-coordinate geometry to ten Co+1.22+ atoms. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to two equivalent Sm3+ and four Co+1.22+ atoms to form corner-sharing CSm2Co4 octahedra. The corner-sharing octahedra tilt angles range from 37–86°. In the second C4- site, C4- is bonded to two equivalent Sm3+ and four equivalent Co+1.22+ atoms to form corner-sharing CSm2Co4 octahedra. The corner-sharing octahedral tilt angles are 86°.