DOI: 10.17188/1717724
title: Materials Data on TaCoNi2 by Materials Project

description: TaCoNi2 is beta Cu3Ti-derived structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded to four Co and eight Ni atoms to form TaCo4Ni8 cuboctahedra that share corners with four equivalent NiTa4Co4Ni4 cuboctahedra, corners with six equivalent TaCo4Ni8 cuboctahedra, corners with eight CoTa4Co2Ni6 cuboctahedra, edges with four CoTa4Co2Ni6 cuboctahedra, edges with fourteen NiTa4Co4Ni4 cuboctahedra, faces with four CoTa4Co2Ni6 cuboctahedra, faces with eight TaCo4Ni8 cuboctahedra, and faces with eight NiTa4Co4Ni4 cuboctahedra. All Ta–Co bond lengths are 2.59 Å. There are four shorter (2.61 Å) and four longer (2.62 Å) Ta–Ni bond lengths. In the second Ta site, Ta is bonded to four Co and eight Ni atoms to form TaCo4Ni8 cuboctahedra that share corners with six equivalent TaCo4Ni8 cuboctahedra, corners with twelve NiTa4Co2Ni6 cuboctahedra, edges with eight CoTa4Co2Ni6 cuboctahedra, edges with ten NiTa4Co4Ni4 cuboctahedra, faces with four CoTa4Co2Ni6 cuboctahedra, faces with eight TaCo4Ni8 cuboctahedra, and faces with eight NiTa4Co4Ni4 cuboctahedra. All Ta–Co bond lengths are 2.61 Å. There are a spread of Ta–Ni bond distances ranging from 2.58–2.62 Å. There are three inequivalent Co sites. In the first Co site, Co is bonded to four Ta, two equivalent Co, and six Ni atoms to form distorted CoTa4Co2Ni6 cuboctahedra that share corners with four equivalent TaCo4Ni8 cuboctahedra, corners with four equivalent NiTa4Co4Ni4 cuboctahedra, corners with ten CoTa4Co2Ni6 cuboctahedra, edges with two equivalent CoTa4Co2Ni6 cuboctahedra, edges with six TaCo4Ni8 cuboctahedra, edges with ten NiTa4Co4Ni4 cuboctahedra, faces with four TaCo4Ni8 cuboctahedra, faces with four CoTa4Co2Ni6 cuboctahedra, and faces with twelve NiTa4Co4Ni4 cuboctahedra. There are one shorter (2.51 Å) and one longer (2.73 Å) Co–Co bond lengths. There are a spread of Co–Ni bond distances ranging from 2.50–2.68 Å. In the second Co site, Co is bonded to four Ta, two equivalent Co, and six Ni atoms to form distorted CoTa4Co2Ni6 cuboctahedra that share corners with four equivalent TaCo4Ni8 cuboctahedra, corners with four equivalent NiTa4Co4Ni4 cuboctahedra, corners with ten CoTa4Co2Ni6 cuboctahedra, edges with two equivalent CoTa4Co2Ni6 cuboctahedra, edges with six TaCo4Ni8 cuboctahedra, edges with ten NiTa4Co4Ni4 cuboctahedra, faces with four TaCo4Ni8 cuboctahedra, faces with four CoTa4Co2Ni6 cuboctahedra, and faces with twelve NiTa4Co4Ni4 cuboctahedra. There are a spread of Co–Ni bond distances ranging from 2.50–2.68 Å. In the third Co site, Co is bonded to four Ta, two equivalent Co, and six Ni atoms to form distorted CoTa4Co2Ni6 cuboctahedra that share corners with four equivalent TaCo4Ni8 cuboctahedra, corners with four equivalent NiTa4Co4Ni4 cuboctahedra, corners with ten CoTa4Co2Ni6 cuboctahedra, edges with two equivalent CoTa4Co2Ni6 cuboctahedra, edges with six TaCo4Ni8 cuboctahedra, edges with ten NiTa4Co4Ni4 cuboctahedra, faces with four TaCo4Ni8 cuboctahedra, faces with four CoTa4Co2Ni6 cuboctahedra, and faces with twelve NiTa4Co4Ni4 cuboctahedra. Both Co–Ta bond lengths are 2.61 Å. There are one shorter (2.51 Å) and one longer (2.73 Å) Co–Co bond lengths. There are a spread of Co–Ni bond distances ranging from 2.50–2.68 Å. There are four inequivalent Ni sites. In the first Ni site, Ni is bonded to four Ta, four Co, and four Ni atoms to form NiTa4Co4Ni4 cuboctahedra that share corners with four equivalent TaCo4Ni8 cuboctahedra, corners with six equivalent NiTa4Co4Ni4 cuboctahedra, corners with eight CoTa4Co2Ni6 cuboctahedra, edges with four CoTa4Co2Ni6 cuboctahedra, edges with six TaCo4Ni8 cuboctahedra, edges with eight NiTa4Co2Ni6 cuboctahedra, faces with four TaCo4Ni8 cuboctahedra, faces with four CoTa4Co2Ni6 cuboctahedra, and faces with twelve NiTa4Co4Ni4 cuboctahedra. All Ni–Ni bond lengths are 2.55 Å. In the second Ni site, Ni is bonded to four Ta, two equivalent Co, and six Ni atoms to form distorted NiTa4Co2Ni6 cuboctahedra that share corners with four equivalent TaCo4Ni8 cuboctahedra, corners with fourteen NiTa4Co2Ni6 cuboctahedra, edges with four equivalent CoTa4Co2Ni6 cuboctahedra, edges with six TaCo4Ni8 cuboctahedra, edges with eight NiTa4Co4Ni4 cuboctahedra, faces with four TaCo4Ni8 cuboctahedra, faces with eight CoTa4Co2Ni6 cuboctahedra, and faces with eight NiTa4Co4Ni4 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.49–2.72 Å. In the third Ni site, Ni is bonded to four Ta, two equivalent Co, and six Ni atoms to form distorted NiTa4Co2Ni6 cuboctahedra that share corners with four equivalent TaCo4Ni8 cuboctahedra, corners with fourteen NiTa4Co2Ni6 cuboctahedra, edges with four equivalent CoTa4Co2Ni6 cuboctahedra, edges with six TaCo4Ni8 cuboctahedra, edges with eight NiTa4Co4Ni4 cuboctahedra, faces with four TaCo4Ni8 cuboctahedra, faces with eight CoTa4Co2Ni6 cuboctahedra, and faces with eight NiTa4Co4Ni4 cuboctahedra. There are one shorter (2.49 Å) and one longer (2.69 Å) Ni–Ni bond lengths. In the fourth Ni site, Ni is bonded to four Ta, four Co, and four Ni atoms to form distorted NiTa4Co4Ni4 cuboctahedra that share corners with four equivalent TaCo4Ni8 cuboctahedra, corners with fourteen NiTa4Co2Ni6 cuboctahedra, edges with four NiTa4Co2Ni6 cuboctahedra, edges with six TaCo4Ni8 cuboctahedra, edges with eight CoTa4Co2Ni6 cuboctahedra, faces with four TaCo4Ni8 cuboctahedra, faces with four CoTa4Co2Ni6 cuboctahedra, and faces with twelve NiTa4Co4Ni4 cuboctahedra.