Methyl Triphenyl Phosphonium Bromide appears as a white salt that dissolves in polar organic solvents. This bromide salt of a phosphonium cation has many applications. Produced by treating triphenylphosphine with methyl bromide, it finds use in methylenation via the Wittig reaction and synthesis of an enyne and 9-isopropenyl -phenanthrene. It works as an antineoplastic agent.