Useful compositions are prepared by incorporating into organic materials, crystalline lithium aluminates which conform substantially to the empirical formula(LiA.sub.x).sub.y.2Al(OH).sub.3.nH.sub.2 Owhere A represents one or more anions and/or negative-valence radicals,where x represents a quantity of A ions and/or radicals sufficient to substantially satisfy the valence requirements of the Li,where y is a numerical value sufficient to maintain the crystalline structure,and where n represents the number of waters of hydration, if any.