Inexpensive alkali earth metal
oxides (mgo and cao) feature high theoretical co2 uptakes, but suffer from poor cyclic stability and slow kinetics.
It turned out that Upsalite had the highest surface area measured for an alkali earth metal
carbonate; 800 square meters per gram.
Alkali or alkali earth metal compounds in which, for instance, the anion is a polymeric sulphonated phenol  are patented as deposit control agents.
The most essential compounds as fuel catalysts are alkali or alkali earth metal derivatives, especially potassium salts of organic acids soluble in petrol.
These hybrids involve interlayer or exchangeable metal cations to balance charges like alkali metals or alkali earth metals
. Suitable ionic groups include onium ions such as ammonium, phosphonium, or sulfonium derivatives of aliphatic, aromatic, oraryl-aliphatic amines, phosphines, and sulfides.