Chemical similarities between Li and Mg:
(1) Their reaction with cold water is slow.
(2) The solubility of the oxides of Li and Mg in water is low. At high temperature, the hydroxides decompose.
2LiOHHeat−−−→Li2O+H2O
Mg(OH)2Heat−−−→MgO+H2O.
(3) They form nitrides by reaction with nitrogen.
6Li+N2heat−−→2Li3N
3Mg+N2heat−−→Mg3N2
(4) They do not form peroxides or superoxies.
(5) They form covalent carbonates which decompose on heating.
Li2CO3heat−−→Li2O+CO2
MgCO3heat−−→MgO+CO2
(6) They do not form solid bicarbonates.
(7) Their covalent chlorides are soluble in ethanol.
(8) Their chlorides are deliquescent and crystallize from aqueous solution as hydrates such as LiCl2.2H2O and MgCl2.8H2O