The yields of e_aq^-, e_aq^-+OD and e_aq^-+D+OD have been measured in D₂O at ambient temperature as a function of scavenger concentration. At scavenging powers ⩽10⁷ s^-1G(e_aq^-) is 10% larger than its value in H₂O, but for scavenging powers 3×10⁸ s^-1 the yields of e_aq^-, e_aq^-+OD and e_aq^-+D+OD are the same in both solvents, indicating that scavenging in the spurs suppresses the reactions leading to the different primary yields. The absorption spectrum of OD is found to be very similar to that of OH, comprising a weak band rising into the UV between 320 and 220 nm with ε₂₅₀=50±2 mol^-1 at 20°C. The shape of the band is the same at 200°C. Rate constants for the reactions OD+OD and D+OD have been measured up to 200°C, on the assumption that ε₂₅₀ for OD is independent of temperature. As with the corresponding reactions in H₂O, they show non-linear Arrhenius behaviour, being close to the diffusion-controlled value at ambient temperature, but an order of magnitude less than this value at 200°C. The values of the rate constants are very similar in both solvents.