Materials Data on KAlSi2 by Materials Project
KAlSi2 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. K is bonded in a 9-coordinate geometry to three equivalent Al and six Si atoms. There are a spread of K–Al bond distances ranging from 3.27–3.33 Å. There are a spread of K–Si bond distances ranging from 3.28–3.33 Å. Al is bonded in a 7-coordinate geometry to three equivalent K and four Si atoms. There are one shorter (2.60 Å) and three longer (2.61 Å) Al–Si bond lengths. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 2-coordinate geometry to three equivalent K, two equivalent Al, and two equivalent Si atoms. Both Si–Si bond lengths are 2.47 Å. In the second Si site, Si is bonded in a 2-coordinate geometry to three equivalent K, two equivalent Al, and two equivalent Si atoms. Both Si–Si bond lengths are 2.47 Å.