DOE OSTI2020
Ti13Co8Al9 crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are five inequivalent Ti sites. In the first Ti site, Ti is bonded in a distorted single-bond geometry to two Ti, three Co, and two equivalent Al atoms. There are one shorter (2.91 Å) and one longer (2.94 Å) Ti–Ti bond lengths. There are one shorter (2.41 Å) and two longer (3.05 Å) Ti–Co bond lengths. Both Ti–Al bond lengths are 2.92 Å. In the second Ti site, Ti is bonded in a distorted single-bond geometry to two equivalent Ti, three Co, and three Al atoms. Both Ti–Ti bond lengths are 2.96 Å. There are one shorter (2.44 Å) and two longer (2.99 Å) Ti–Co bond lengths. There are a spread of Ti–Al bond distances ranging from 2.79–3.02 Å. In the third Ti site, Ti is bonded in a 4-coordinate geometry to three equivalent Ti, four Co, and six Al atoms. There are one shorter (2.52 Å) and three longer (2.61 Å) Ti–Co bond lengths. There are three shorter (2.71 Å) and three longer (2.86 Å) Ti–Al bond lengths. In the fourth Ti site, Ti is bonded in a 4-coordinate geometry to three Ti, four Co, and six Al atoms. There are a spread of Ti–Co bond distances ranging from 2.48–2.64 Å. There are a spread of Ti–Al bond distances ranging from 2.71–2.85 Å. In the fifth Ti site, Ti is bonded in a distorted trigonal planar geometry to three Co and four Al atoms. There are two shorter (2.46 Å) and one longer (2.47 Å) Ti–Co bond lengths. There are three shorter (2.76 Å) and one longer (2.91 Å) Ti–Al bond lengths. There are four inequivalent Co sites. In the first Co site, Co is bonded in a 12-coordinate geometry to seven Ti and five Al atoms. There are a spread of Co–Al bond distances ranging from 2.41–2.66 Å. In the second Co site, Co is bonded in a 12-coordinate geometry to four Ti and four Al atoms. There are two shorter (2.43 Å) and two longer (2.65 Å) Co–Al bond lengths. In the third Co site, Co is bonded in a body-centered cubic geometry to four Ti and four Al atoms. All Co–Al bond lengths are 2.45 Å. In the fourth Co site, Co is bonded in an octahedral geometry to six Ti atoms. There are five inequivalent Al sites. In the first Al site, Al is bonded in a 3-coordinate geometry to three equivalent Ti and three equivalent Co atoms. In the second Al site, Al is bonded in a 3-coordinate geometry to three Ti and three Co atoms. In the third Al site, Al is bonded in a 4-coordinate geometry to nine Ti and four Co atoms. In the fourth Al site, Al is bonded in a 4-coordinate geometry to eight Ti, four Co, and one Al atom. The Al–Al bond length is 2.68 Å. In the fifth Al site, Al is bonded in a 3-coordinate geometry to six Ti, three equivalent Co, and three equivalent Al atoms.