Layered hexagonal KLaSe2 (alpha-NaFeO(2)-type) was synthesized using the reactive flux method and analyzed by powder XRD to determine its lattice constants (space group R-3m, a = 4.40508(5) angstrom, c = 22.7838(5) angstrom). NaLaSe2, which normally crystallizes as a disordered rock salt structure with mixed Na+/La + 3 sites. was synthesized through a solid state ion exchange reaction at 585 degrees C from a 1:3 molar ratio mixture of KLaSe(2):Nal. The product of this reaction was hexagonally layered NaLaSe2 (space group R-3m, a = 4.3497(3) angstrom, c = 20.808(2) angstrom) isostructural to KLaSe(2). This product was analyzed by comparison with members of the set of solid solutions Na((1-x))K((x))LaSe(2) to confirm that the extent ion exchange in this reaction was complete. Cubic (disordered) NaLaSe(2) was also reacted with KI to yield the poorly crystalline hexagonally layered product with the approximate formula Na(0.79)K(0.21)LaSe(2). (C) 2008 Elsevier Ltd. All rights reserved.