Syntheses of the new compounds NaBi6O9X (X = Br, I) and the mixed systems Na0.77(3)K0.23(3)Bi6O9I, Rb0.91(3)K0.05(1)Na0.04(2)Bi6O9Br and Rb0.89(4)K0.05(1)Na0.06(3)Bi6O9I

The new compounds NaBi6O9X (X = Br, I) were synthesized. Attempts to synthesize the analogous RbBi6O9X (X = Br, I) compounds yielded mixed systems with about 10% of the Rb atoms replaced by Na and K atoms. Another mixed system, Na0.77(3)K0.23(3)Bi6O9I, was obtained incidentally. The corresponding ABi6O9X compounds with X = Cl or A = Cs could not be obtained. The influence of A and X on the size of the ABi6O9X unit cell is discussed.