The second-order rate constants of gas-phase Lu(D-2(3/2)) with O-2, N2O and CO2 from 348 to 573 K are reported. In all cases, the reactions are relatively fast with small barriers. The disappearance rates are independent of total pressure indicating bimolecular abstraction processes. The bimolecular rate constants (in molecule(-1) cm(3) s(-1)) are described in Arrhenius form by k(O-2) = (2.3+/-0.4) x 10(-10) exp(-3.1 +/- 0.7 kJ mol(-1)/RT), k(N2O) = (2.2 +/- 0.4) x 10(-10) exp(-7.1 +/- 0.8 kJ mol(-1)/RT), k(CO2) = (2.0 +/- 0.6) x 10(-10) exp(-7.6 +/- 1.3 kJ mol(-1)/RT), where the uncertainties are +/-2 sigma.