The rate coefficient, k(1) (298 K)=(5.0+/-1.1)x10(-11) cm(3) molecule(
-1) s(-1), for the reaction, Br+10-->I+BrO (1) was determined by monit
oring the temporal profiles of IO in an excess of Br. The rate coeffic
ient for the reverse reaction, I+BrO-->IO+Br(-1), k(-1) (298 K)=(1.9+/
-1.1)x10(-11) cm(3) molecule(-1) s(-1), was determined by modeling IO
temporal profiles, measured in the presence of BrO and O-3, in which t
he regeneration of IO was observed. From these rate coefficients, the
difference in the heats of formations of IO and BrO, Delta(f)H(0) (298
K) (BrO)-Delta(f)H(0) (298 K) (IO), was calculated to be 0.5+/-0.6 kc
al mol(-1). (C) 1997 Elsevier Science B.V.