(i) Lithium is much harder. Its m.p. and b.p. are higher than the other alkali metals. (ii) Lithium is least reactive but the strongest reducing agent among all the alkali metals. On combustion in air it forms mainly monoxide, Li2O and the nitride, Li3N unlike other alkali metals. (iii) LiCl is deliquescent and crystallises as a hydrate, LiCl.2H2O whereas other alkali metal chlorides do not form hydrates. (iv) Lithium hydrogencarbonate is not obtained in the solid form while all other elements form solid hydrogen carbonates. (v) Lithium unlike other alkali metals forms no ethynide on reaction with ethyne. (vi) Lithium nitrate when heated gives lithium oxide, Li2O, whereas other alkali metal nitrates decompose to give the corresponding nitrite.
(vii) LiF and Li2O are comparatively much less soluble in water than the corresponding compounds of other alkali metals.