Materials Data on KNa2NiO2 by Materials Project
KNa2NiO2 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. K1+ is bonded in a single-bond geometry to one O2- atom. The K–O bond length is 2.84 Å. Na1+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are two shorter (2.31 Å) and two longer (2.47 Å) Na–O bond lengths. Ni1+ is bonded in a linear geometry to two O2- atoms. Both Ni–O bond lengths are 1.80 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one K1+, four equivalent Na1+, and one Ni1+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Na1+ and one Ni1+ atom.
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