This Wittig reagent, also known as 2-Oxoethyltriphenylphosphonium chloride, presents as a slightly pale yellow to reddish yellow crystal powder. It is known to be soluble in water and methanol. For best results, keep container tightly closed and store in a dark place at 2-8°C. (Formylmethyl)triphenylphosphonium Chloride is hygroscopic and is incompatible with oxidizing agents. This chemical is harmful if swallowed and causes serious eye damage.