Materials Data on Sr3CaAl8 by Materials Project
Sr3CaAl8 is Cubic Laves-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are three inequivalent Sr sites. In the first Sr site, Sr is bonded in a 12-coordinate geometry to four Sr and twelve Al atoms. There are one shorter (3.51 Å) and three longer (3.59 Å) Sr–Sr bond lengths. There are a spread of Sr–Al bond distances ranging from 3.41–3.43 Å. In the second Sr site, Sr is bonded in a 12-coordinate geometry to one Sr, three equivalent Ca, and twelve Al atoms. All Sr–Ca bond lengths are 3.58 Å. There are a spread of Sr–Al bond distances ranging from 3.36–3.43 Å. In the third Sr site, Sr is bonded in a 12-coordinate geometry to three equivalent Sr, one Ca, and twelve Al atoms. The Sr–Ca bond length is 3.49 Å. There are a spread of Sr–Al bond distances ranging from 3.41–3.44 Å. Ca is bonded in a 12-coordinate geometry to four Sr and twelve Al atoms. There are a spread of Ca–Al bond distances ranging from 3.36–3.43 Å. There are four inequivalent Al sites. In the first Al site, Al is bonded to three equivalent Sr, three equivalent Ca, and six Al atoms to form AlSr3Ca3Al6 cuboctahedra that share corners with eighteen AlSr6Al6 cuboctahedra, edges with six equivalent AlSr3Ca3Al6 cuboctahedra, and faces with eighteen AlSr4Ca2Al6 cuboctahedra. There are three shorter (2.87 Å) and three longer (2.88 Å) Al–Al bond lengths. In the second Al site, Al is bonded to six Sr and six Al atoms to form AlSr6Al6 cuboctahedra that share corners with eighteen AlSr3Ca3Al6 cuboctahedra, edges with six equivalent AlSr6Al6 cuboctahedra, and faces with eighteen AlSr4Ca2Al6 cuboctahedra. There are three shorter (2.90 Å) and three longer (2.91 Å) Al–Al bond lengths. In the third Al site, Al is bonded to four Sr, two equivalent Ca, and six Al atoms to form AlSr4Ca2Al6 cuboctahedra that share corners with eighteen AlSr3Ca3Al6 cuboctahedra, edges with six AlSr4Ca2Al6 cuboctahedra, and faces with eighteen AlSr3Ca3Al6 cuboctahedra. There are two shorter (2.92 Å) and two longer (2.93 Å) Al–Al bond lengths. In the fourth Al site, Al is bonded to five Sr, one Ca, and six Al atoms to form AlSr5CaAl6 cuboctahedra that share corners with eighteen AlSr3Ca3Al6 cuboctahedra, edges with six AlSr4Ca2Al6 cuboctahedra, and faces with eighteen AlSr3Ca3Al6 cuboctahedra. There are two shorter (2.92 Å) and two longer (2.94 Å) Al–Al bond lengths.