The gas-phase kinetics of the reaction between Cu2 and C2H4 have been
studied as a function of pressure in a fast-flow reactor. The limiting
low-pressure, third-order rate constant for the reaction was found to
be (9.3 +/- 1.4) X 10(-30) cm6 s-1 in He. Modeling studies of this ra
te constant imply that Cu2(C2H4) is bound by at least 20 kcal mol-1.