The reaction rates for (CH)-C-12 and (CD)-C-12 With normal isotopic abundance CO and (CO)-C-13 have been studied at 293 K for pressures between 12.5 and 500 Torr and at 100 Torr for temperatures between 293 and 650 K. The pressure and temperature dependence of the addition reaction of CH with CO have been measured. The addition rate coefficient can be fit to the expression 7.2+/-0.3x10(-12) (T/293)(-2.4+/-0.2) cm(3) molecule(-1) s(-1) at 100 Torr total pressure (He buffer). A fit of the pressure dependence to a Tree expression with F-c=0.6 yields a low-pressure rate constant (k(0)) of 2.4+/-0.3x10(-30) cm(6) molecule(-2) s(-1). The rate for carbon atom exchange has been measured by comparison of the C-13 labeled and unlabeled reaction rates. The isotopic exchange reaction is 1.0+/-0.2x10(-12) cm(3) molecule(-1) s(-1) at 20 Torr. The deuterium isotope effect on the exchange rate is large, with an inverse kinetic isotope effect (k(H)/k(D))=0.28+/-0.08 at 20 Torr. This inverse isotope effect reflects the competition between collisional stabilization and isomerization, and is a convolution of isotope effects for the isomerization, unimolecular dissociation, and stabilization rates. The experimental results are consistent with a mechanism for exchange that involves isomerization of an HCCO adduct via an oxiryl intermediate, and indicate that insertion into the C-O bond is not important in this reaction.