Mild dehydration reagent in organic synthesis; used in conversion of alcohols to olefins, and diols to epoxides. Prepn: J. C. Martin, R. J. Arhart, J. Am. Chem. Soc. 93, 2341 (1971) DOI; idem et al., Org. Synth. coll. vol. VI, 163 (1988); and chemical properties: R. J. Arhart, J. C. Martin, J. Am. Chem. Soc. 94, 4997 (1972) DOI. X-ray crystal structure: I. C. Paul et al., ibid. 93, 6674 (1971) DOI; 94, 5010 (1972). Synthetic applications in dehydration of alcohols: J. C. Martin, R. J. Arhart, ibid. 93, 4327 (1971) DOI; R. J. Arhart, J. C. Martin, ibid. 94, 5003 (1972) DOI; J. C. Martin et al., ibid. 96, 4604 (1974) DOI; F. Yokokawa, T. Shioiri, Tetrahedron Lett. 43, 8679 (2002) DOI; in oxidation of secondary amines to imines: J. A. Franz, J. C. Martin, J. Am. Chem. Soc. 97, 583 (1975) DOI; in cleavage of secondary amides: J. A. Franz, J. C. Martin, J. Am. Chem. Soc. 97, 6137 (1975) DOI.