The standard molar enthalpies of solution of CeI3(s) in 0.250 mol.dm(-
3) HCl(aq) and LaI3(s) in 1.006 mol.dm(-3) HCl(aq) have been measured.
From these values the standard molar enthalpies of formation have bee
n derived: Delta(f)H(m)(degrees)(CeI3,s,298.15 K) = -(669.3+/-0.g)kJ.m
ol(-1)and Delta(f)H(m)(degrees)(LaI3,s,298.15 K)= -(668.9+/-1.2) kJ.mo
l(-1).