Replacement of Na+ by Li+ has been achieved for sodalites of composition Na-8[GaSiO4](6)X-2 and Na-8[AlGeO4](6)X-2, where X is a halide, via nitrate melt at 240 degrees C. The resultant materials have been analyzed by Rietveld analysis of neutron powder diffraction data, and the derived structural parameters are compared with the parent sodium sodalites. The framework collapse associated with lithium exchange is principally accommodated by cooperative rotations about the (4) over bar axis and a decrease in the framework T-O-T bond angle. Complete replacement of sodium by lithium was possible for all of the gallosilicate halide sodalites as well as the aluminogermanate bromide and iodide sodalites. In the case of aluminogermanate chloride sodalite, the required level of structure collapse seems to preclude full replacement of sodium by lithium.