Materials Data on Al17(SiPd2)4 by Materials Project
Al17(Pd2Si)4 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. there are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 10-coordinate geometry to nine Al and one Si atom. There are a spread of Pd–Al bond distances ranging from 2.56–2.78 Å. The Pd–Si bond length is 2.65 Å. In the second Pd site, Pd is bonded in a 10-coordinate geometry to eight Al and two equivalent Si atoms. There are a spread of Pd–Al bond distances ranging from 2.55–3.01 Å. There are one shorter (2.59 Å) and one longer (2.65 Å) Pd–Si bond lengths. There are five inequivalent Al sites. In the first Al site, Al is bonded to four equivalent Pd atoms to form distorted corner-sharing AlPd4 tetrahedra. In the second Al site, Al is bonded in a 4-coordinate geometry to four Pd and two equivalent Si atoms. There are one shorter (2.77 Å) and one longer (2.79 Å) Al–Si bond lengths. In the third Al site, Al is bonded to four Pd atoms to form a mixture of distorted corner and edge-sharing AlPd4 tetrahedra. In the fourth Al site, Al is bonded in a 4-coordinate geometry to four Pd and one Si atom. The Al–Si bond length is 2.93 Å. In the fifth Al site, Al is bonded in a 1-coordinate geometry to four Pd and two equivalent Si atoms. There are one shorter (2.60 Å) and one longer (2.78 Å) Al–Si bond lengths. Si is bonded in a 9-coordinate geometry to three Pd, five Al, and one Si atom. The Si–Si bond length is 2.57 Å.