Organic acid anhydride Organic acid anhydride An organic acid anhydride is an acid anhydride that is an organic compound. An acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom. A common type of organic acid anhydride is a carboxylic anhydride, where the parent acid is a carboxylic acid, the formula of the anhydride being (RC(O))O. Symmetrical acid anhydrides of this type are named by replacing the word "acid" in the name of the parent carboxylic acid by the word "anhydride". Thus, (CHCO)O is called "acetic anhydride." Mixed (or unsymmetrical) acid anhydrides, such as acetic formic anhydride
Pyrosilicic acid the original solution is converted to pyrosilicic acid, which persists for 10 minutes or more. Pyrosilicic acid can also be obtained by controlled hydrolysis of the corresponding organic ester, such as hexaethyl pyrosilicate, with dilute sulfuric acid. Pyrosilicic acid Pyrosilicic acid is the chemical compound with formula , or -O-. It is one of the silicic acids. It has never been isolated in pure form, but it is assumed to be present in solutions of silicon dioxide (silica) in water, in equilibrium with other silicic acids and silicate ions. The salts of pyrosilicic acid are called pyrosilicates, such as sodium