The reaction between the aqueous chromyl ion, CraqO2+, and Br- is acid-catalyzed and generates Br-2. Kinetic studies that utilized a superoxochromium ion, CraqOO2+, as a kinetic probe yielded a mixed third-order rate law, -d[CraqO2+]/dt = k[Cr-aq O2+] [Br-][H+], where k = 608 +/- M-2 s(-1). Experimental data strongly favor a one-electron mechanism, but the reaction is much faster than predicted on the basis of the reduction potential for the Br-center dot/Br- couple. The reduction of CraqO2+ by transition-metal complexes, on the other hand, exhibits "normal" behavior, that is, k = (1.37 x 10(3) + 1.94 x 10(3) [H+]) M-1 s(-1) for Os(1,10-tris-phenanthroline)(3)(2+) and < 10 M-1 s(-1) for Ru(2,2'-bipyridine)(3)(2+) at 0.1 M H+. The reduction of CraqOO2+ by Br-2(center dot-) takes place with a rate constant k = (1,23 +/- 0.20) x 10(9) M-1 s(-1), as determined by laser-flash photolysis.