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 ABi(6)O(9)X compounds with X = Cl or A = Cs could not be obtained. The influence of A and X on the size of the ABi(6)O(9)X unit cell is discussed. (c) 2006 Elsevier Ltd. All rights reserved.