Benzophenone is the organic compound with the formula (C6H5)2CO. It generally abbreviated Ph2CO. Substituted benzophenones such as oxybenzone and dioxybenzone are used in sunscreen. Benzophenone also called dphenylmethanone can be prepared by the reaction of benzene with carbon tetrachloride followed by hydrolysis of the resulting diphenyldichloromethane. It is a common photosensitizer in photochemistry. It crosses from the S1 state into the triplet state with nearly 100 % yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl radical.