The highly exothermic reaction of chromium trioxide when added to an excess of pyridine leads to the formation the CrO3 • 2 Py complex (Sarett Reagent). Compared to the Jones Reagent, Sarett Reagent allows the oxidation of various primary alcohols to aldehydes due to the non-aqueous conditions (see Jones Oxidation for an explanation). Unfortunately, the complex is highly hygroscopic and the preparation of the reagent is not without risk because the solvent occasionally catches fire during preparation. In addition, the use of pyridine as solvent does not permit the oxidation of base-sensitive substrates.