Figure 4

Crystal structure of (a) KCa₂Nb₃O₁₀ viewed in [100] and pseudo 2D [Ca₂Nb₃O₁₀]⁻ viewed in (b) [100] and (c) [001] (red spheres, Calcium; gray, Oxygen and purple, Potassium); Nb (shown with green spheres) is located within the centre of the octahedra.