CaSO3 is also known as calcium sulfate(II) or calcium sulfite. In English, we call it Calcium sulfite. This is a solid, colorless, odorless and non-flammable substance. The molecule of CaSO3 consists of one calcium atom, one sulfur atom and three oxygen atoms. The molecular weight of CaSO3 is 120.15 g/mol.
The ionic structure of CaSO3 is Ca2+ and SO3^2-. In solution, CaSO3 has a neutral or slightly alkaline pH because it has the ability to form hydroxide ions from reaction with water.
CaSO3 exhibits quite special chemical properties. It can react with acid to form SO2 gas, with metals to form sulfides and oxygen. But it does not easily react with non-metals or salts.
The common chemical equation of CaSO3 with acid is: CaSO3 + 2HCl -> CaCl2 + H2O + SO2. With metals like copper, the chemical equation can be written as: 2Cu + CaSO3 -> Cu2S + CaO.
CaSO3 is usually synthesized in the lab from the chemical reaction between Ca(OH)2 and SO2. In industry, CaSO3 is produced from burning calcium in the air, then sulfurizing to obtain the product.