C3ACaSO412H2O

C3ACaSO412H2O appears to be a chemical notation describing a composition that includes tricalcium aluminate (C3A), calcium sulfate (CaSO4), and twelve water molecules. In cement chemistry, C3A corresponds to the nominal formula 3CaO·Al2O3, and the symbols are often used to denote phases and hydrates formed during cement hydration.

There is no widely recognized mineral or pure compound with the exact formula C3ACaSO412H2O in standard chemical databases. The notation more likely represents a hydrated intermediate or a stoichiometric representation used in discussions of cement hydration, particularly the interaction of C3A with sulfate sources such as gypsum (CaSO4·2H2O) in the presence of water.

In ordinary Portland cement hydration, C3A reacts with calcium sulfate and water to form ettringite, a hydrated calcium sulfoaluminate solid with the formula Ca6Al2(SO4)3(OH)12·26H2O. If sulfate supply is limited, monosulfate and other phases can form. The depiction C3A CaSO4 12H2O could describe an early or intermediate hydration product under certain conditions, but the exact structure and stability depend on temperature, pH, and sulfate availability.

As a result, C3ACaSO412H2O is not a standard, well-defined material with a fixed crystal structure; it is best understood as a representation used in discussing cement hydration equilibria rather than a discrete mineral. See also ettringite, monosulfate, tricalcium aluminate, and calcium sulfate.