Cellulose nitrate is also known as celloidin, collodion, low viscosity nitrocellulose (LVN) necoloidine, nitrocellulose, parlodion, pyroxylin, and soluble gun cotton. (Some of these are trade-names; for even more synonyms, see the Merck Index, under pyroxylin.) It is made by treating cellulose with a mixture of concentrated nitric and sulfuric acids, This converts some of the hydroxyl (-OH) groups of cellulose to nitrate ester (-ONO2) groups. The molecular size and physical form of the original cellulose and the proportion of nitrated hydroxyl groups determine the properties of the product. It is useful in microtechnique because of its physical properties and its unusual responses to solvents and other liquids.