Triphenylphosphine oxide (often abbreviated TPPO) is the
chemical compound with the formula OP(C
6H
5)
3, also written as Ph
3PO or PPh
3O (Ph =
C6H5). This colourless crystalline compound is a common side product in reactions involving
triphenylphosphine. It is a popular reagent to induce the
crystallizing of chemical compounds.