Precession and Weissenberg films of a single crystal of synthesized brannerite show that the compound is monoclinic, C2/m with a = 9.87, b = 3.76, c = 6.95 Aa, beta = 119 degrees 30'. The cell contains 2[UTi 2 O 6 ]. Sp. gr. (meas.) = 6.35, (calc.) = 6.36. The cell constants and space group are compatible with the forms observed by Pabst on natural crystals in terms of the theoretical form development predicted by the Donnay generalization of the Bravais law. It suggests that brannerite regains its original structure on ignition.