Materials Data on K2NiO2 by Materials Project
K2NiO2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. K1+ is bonded to five equivalent O2- atoms to form a mixture of edge and corner-sharing KO5 square pyramids. There are one shorter (2.72 Å) and four longer (2.82 Å) K–O bond lengths. Ni2+ is bonded in a linear geometry to two equivalent O2- atoms. Both Ni–O bond lengths are 1.72 Å. O2- is bonded to five equivalent K1+ and one Ni2+ atom to form a mixture of distorted edge and corner-sharing OK5Ni octahedra. The corner-sharing octahedra tilt angles range from 0–14°.
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