Materials Data on K4BeAs2 by Materials Project
K4BeAs2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a trigonal non-coplanar geometry to three equivalent As3- atoms. All K–As bond lengths are 3.44 Å. In the second K1+ site, K1+ is bonded to four equivalent As3- atoms to form a mixture of corner and edge-sharing KAs4 tetrahedra. There are one shorter (3.35 Å) and three longer (3.50 Å) K–As bond lengths. Be2+ is bonded in a linear geometry to two equivalent As3- atoms. Both Be–As bond lengths are 2.09 Å. As3- is bonded in a distorted body-centered cubic geometry to seven K1+ and one Be2+ atom.
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