All the carbonates in this group undergo thermal decomposition to the metal oxide and carbon dioxide gas. The term "thermal decomposition" describes splitting up a compound by heating it.
All the Group 2 carbonates and their resulting oxides exist as white solids. If "X" represents any one of the elements, the following describes this decomposition:XCO3(s)→XO(s)+CO2(g)
Down the group, the carbonates require more heating to decompose.The carbonates become more thermally stable down the group.
Down the group, the nitrates must also be heated more strongly before they will decompose.