What is Cr2O3C2? Important knowledge about Cr2O3C2.

I’m sorry, but Cr₂O₃C₂ is not the correct formula for a chemical substance. It might be a typing error or misunderstanding. Chemical substances usually have formulas according to the IUPAC (International Union of Pure and Applied Chemistry) rules. Atoms and molecules are usually represented by letters from the Periodic Table, with subscript numbers indicating the number of atoms in each molecule.

If you are trying to refer to chromium oxide (Cr₂O₃) or ethyne (C₂H₂), I can provide information about these substances. However, if you are looking for information about another chemical substance, please provide the correct formula.