Bis(triphenylphosphineoxide) manganese(III) chloride is a coordination complex of manganese(III) chloride. Unlike most compounds containing "Mn(III)Cl<sub>3</sub>", [MnCl<sub>3</sub>(OPPh<sub>3</sub>)<sub>2</sub>] can be stored under normal laboratory conditions. It is a blue, paramagnetic solid.
Treatment of meta-stable solutions of Mn(III)Cl<sub>3</sub> with triphenylphosphine oxide results in precipitation of solid [MnCl<sub>3</sub>(OPPh<sub>3</sub>)<sub>2</sub>]. This compound was first prepared using the thermally unstable ethereal adduct Mn<sup>III</sup>(dioxane)Cl<sub>3</sub>. A convenient synthesis starts from Mn(OAc)<sub>2</sub>, trimethylsilylchloride, and potassium permanganate.
[MnCl<sub>3</sub>(OPPh<sub>3</sub>)<sub>2</sub>] can be used as a starting material in coordination chemistry.
[MnCl<sub>3</sub>(OPPh<sub>3</sub>)<sub>2</sub>] can also be used as a stoichiometric reagent in alkene dihalogenation reactions.