Trifluoromethanesulfonic acid exothermically reacts with metal carbonates, hydroxides, and oxides. Other important mineral groups include the native elements, sulfides, oxides, halides, carbonates, sulfates, and phosphates. They are usually obtained through minerals such as sulfides, carbonates, and silicates. Calcium carbonate shares the typical properties of other carbonates. Paleozoic and upper Proterozoic carbonates and terrigenous sediments. The alkaline earth metal oxides are formed from the thermal decomposition of the corresponding carbonates. The Tobosa basin contained shelf carbonates and shales. Coal balls are calcareous permineralizations of peat by calcium and magnesium carbonates. Upon melting with alkaline carbonates and sulfur, germanium compounds form salts known as thiogermanates. Some of the sediments are marine carbonates and clays. Some important minerals are carbonates, notably calcite. For similar reasons, most alkali metal carbonates are not soluble in water. Discolorations can result from mineral impurities such as pyrites or barium carbonates. These widespread carbonates and other sedimentary deposits make the Cretaceous rock record especially fine. For this reason, EDTA is able to dissolve deposits of metal oxides and carbonates.