Materials Data on Cs2NaAs7 by Materials Project
Cs2NaAs7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten As+0.43- atoms. There are a spread of Cs–As bond distances ranging from 3.72–4.21 Å. In the second Cs1+ site, Cs1+ is bonded in a 1-coordinate geometry to ten As+0.43- atoms. There are a spread of Cs–As bond distances ranging from 3.85–4.41 Å. Na1+ is bonded in a 5-coordinate geometry to six As+0.43- atoms. There are a spread of Na–As bond distances ranging from 3.00–3.49 Å. There are seven inequivalent As+0.43- sites. In the first As+0.43- site, As+0.43- is bonded in a 6-coordinate geometry to two equivalent Cs1+, one Na1+, and three As+0.43- atoms. There are a spread of As–As bond distances ranging from 2.40–2.55 Å. In the second As+0.43- site, As+0.43- is bonded in a 5-coordinate geometry to one Cs1+, two equivalent Na1+, and two As+0.43- atoms. The As–As bond length is 2.45 Å. In the third As+0.43- site, As+0.43- is bonded in a 5-coordinate geometry to five Cs1+ and two As+0.43- atoms. There are one shorter (2.39 Å) and one longer (2.45 Å) As–As bond lengths. In the fourth As+0.43- site, As+0.43- is bonded in a 7-coordinate geometry to three Cs1+, one Na1+, and three As+0.43- atoms. The As–As bond length is 2.47 Å. In the fifth As+0.43- site, As+0.43- is bonded to four Cs1+ and three As+0.43- atoms to form distorted edge-sharing AsCs4As3 pentagonal bipyramids. The As–As bond length is 2.57 Å. In the sixth As+0.43- site, As+0.43- is bonded in a 1-coordinate geometry to three Cs1+, one Na1+, and two As+0.43- atoms. The As–As bond length is 2.39 Å. In the seventh As+0.43- site, As+0.43- is bonded in a 1-coordinate geometry to two Cs1+, one Na1+, and three As+0.43- atoms.