Materials Data on Tb2Al17 by Materials Project

Tb2Al17 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Tb sites. In the first Tb site, Tb is bonded in a 12-coordinate geometry to eighteen Al atoms. There are a spread of Tb–Al bond distances ranging from 3.28–3.63 Å. In the second Tb site, Tb is bonded in a 2-coordinate geometry to twenty Al atoms. There are a spread of Tb–Al bond distances ranging from 3.12–3.53 Å. There are eight inequivalent Al sites. In the first Al site, Al is bonded in a 2-coordinate geometry to one Tb and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.64–3.11 Å. In the second Al site, Al is bonded to two equivalent Tb and ten Al atoms to form AlTb2Al10 cuboctahedra that share corners with fourteen AlTb2Al10 cuboctahedra, edges with six AlTb3Al9 cuboctahedra, and faces with ten AlTb2Al10 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.67–2.78 Å. In the third Al site, Al is bonded to two equivalent Tb and ten Al atoms to form AlTb2Al10 cuboctahedra that share corners with fourteen AlTb2Al10 cuboctahedra, edges with six AlTb3Al9 cuboctahedra, and faces with ten AlTb2Al10 cuboctahedra. There are four shorter (2.68 Å) and four longer (2.78 Å) Al–Al bond lengths. In the fourth Al site, Al is bonded in a 12-coordinate geometry to two Tb and ten Al atoms. There are a spread of Al–Al bond distances ranging from 2.74–2.93 Å. In the fifth Al site, Al is bonded in a 12-coordinate geometry to two Tb and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.73–2.96 Å. In the sixth Al site, Al is bonded in a 12-coordinate geometry to two Tb and eight Al atoms. There are two shorter (2.75 Å) and two longer (2.83 Å) Al–Al bond lengths. In the seventh Al site, Al is bonded to three Tb and nine Al atoms to form a mixture of distorted edge, face, and corner-sharing AlTb3Al9 cuboctahedra. Both Al–Al bond lengths are 2.71 Å. In the eighth Al site, Al is bonded to three Tb and nine Al atoms to form a mixture of distorted edge, face, and corner-sharing AlTb3Al9 cuboctahedra.