Zur Kenntnis von Na4[CrO4]

On Na₄(CrO₄) Dark-green single crystals of Na₄CrO₄] were obtained for the first time. (Na₂O/Cr₂O₃; Na:Cr = 4:1 not exactly closed Ni-tube; 1000°C; 30 d). It is isostructural to Na₄(CoO₄); space group P1 , a = 859.7 pm, b = 569.8 pm, c = 640 pm, α = 124°C, β = 98.4°, γ = 98.9°, Z = 2. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated.