The gas phase depletion kinetics of Nb(a(6)D(J),a(4)F(J)) in the presence of O-2, SO2, CO2, N2O, and NO are reported. Niobium atoms were produced by the 248 nm photodissociation of Nb(C5H5)(CO)(4) and detected by laser-induced fluorescence. The ground term of Nb(4d(4)5s(1)a(6)D(J)) reacts at or above the collision rate with all of the aforementioned oxidants. The first excited term, Nb(4d(3)5s(2)a(4)F(J)), is not as reactive with these oxidants. Results are interpreted in terms of long-range attractions and valence interactions. Additionally, we report reaction rate constants for ground state Nb interacting with N-2, CH4, and SF6. Nb(a(6)D(J)) is unreactive toward CH4. Nb(a(6)D(J)) + N-2 is pressure dependent at 297 K with k(0) = (2.6 +/- 0.3) x 10(-32) cm(6) s(-1) and k infinity = (4.1 +/- 0.5) x 10(-13) cm(3) s(-1). Nb(a(6)D(J)) + SF6 is temperature dependent with the rate constants given by k(T) = (1.2 +/- 0.3) x 10(-10) exp[-(4.8 +/- 0.2) kcal mol(-1)/RT] cm(3) s(-1). Depletion of the a(4)F(J) term by N-2, SF6, and CH4 is J-dependent.