# Chemical formula of Lactic acid

Formula of Lactic acid is given as C3H6O3, can't this be divided by the common factor3, and written as CH2O?

• This was supposed to be a molecular formula. You don't divide molecules. – Ivan Neretin Aug 31 '18 at 6:25
• FWIW, CH2O is the correct "empirical formula" for lactic acid, as you would calculate from elemental analysis. – iad22agp Aug 31 '18 at 9:54
• Basically, you can simplify or "divide" a molecular formula only if it really makes sense. – SteffX Aug 31 '18 at 15:31
• Basically, a given molecule has a unique (molecular) formula. However, some molecules have a tendency to associate to form bigger molecules. Only in that case can you simplify or "divide" a molecular formula. For example, elemental sulfur (S) is usually found in nature as S8 and then you can consider its true formula is S. Also P4S10 is a dimer of P2O5; you have P4S10 in your flask but you can consider P2O5 in your calculations. – SteffX Aug 31 '18 at 15:37

You have initially tagged your question "structural formula", however $\ce{C3H6O3}$ is somewhat ambigous in this respect, and besides lactic acid can represent its isomer 3-hydroxypropionic acid, methoxyacetic acid, and almost completely different compounds like dihydroxyacetone, dimethyl carbonate, glyceraldehyde or trioxanes, not speaking of the second one $\ce{CH2O}$ (formaldehyde or ethylene oxide). Well, these are not structural formulas at all.