Syntheses of the new compounds NaBi{sub 6}O{sub 9}X (X = Br, I) and the mixed systems Na{sub 0.77(3)}K{sub 0.23(3)}Bi{sub 6}O{sub 9}I, Rb{sub 0.91(3)}K{sub 0.05(1)}Na{sub 0.04(2)}Bi{sub 6}O{sub 9}Br and Rb{sub 0.89(4)}K{sub 0.05(1)}Na{sub 0.06(3)}Bi{sub 6}O{sub 9}I

The new compounds NaBi{sub 6}O{sub 9}X (X = Br, I) were synthesized. Attempts to synthesize the analogous RbBi{sub 6}O{sub 9}X (X = Br, I) compounds yielded mixed systems with about 10% of the Rb atoms replaced by Na and K atoms. Another mixed system, Na{sub 0.77(3)}K{sub 0.23(3)}Bi{sub 6}O{sub 9}I, was obtained incidentally. The corresponding ABi{sub 6}O{sub 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{sub 6}O{sub 9}X unit cell is discussed.