Synthesis and ab initio X‐ray powder diffraction structure of the new alkali and alkali earth metal borate NaCa(BO3)

A sodium calcium borate, NaCaBO₃, has been synthesized by the solid‐state reaction method and the structure solved from X‐ray powder diffraction data. The compound crystallizes in space group Pmmn and has a desired structure type containing isolated planar BO₃³⁻ anions. Mixed occupancy is found to exist in the Ca site, with partial replacement by Na. One Ca/Na mixed atom and one Na atom are at sites with mm2 symmetry, and a second Ca/Na mixed atom, an Na atom, two B and two O atoms are on mirror planes.