Mediates oxidative catalytic transformations of organic compounds with molecular oxygen. Prepn: L. Cohn, Ann. 205, 295 (1880); H. Gross, I. Keitel, J. Prakt. Chem. 311, 692 (1969). Crystal structure: F.-M. Miao et al., Acta Crystallogr. C51, 712 (1995). Transition metal free oxidation reactions: C. Einhorn et al., Chem. Commun. 1997, 447; epoxidation of alkenes: T. Iwahama et al., Heterocycles 52, 693 (2000). Transition metal cocatalysis in alkane oxidation: Y. Ishii et al., J. Org. Chem. 61, 4520 (1996); in hydroxylation of fatty acids: M. A. Oakley et al., J. Mol. Catal. A 150, 105 (1999). Description of catalytic mechanisms: Y. Ishii, S. Sakaguchi, Catal. Surv. Jpn. 3, 27 (1999).