Uranium monocarbide was synthesized on a 500- to 1000-g scale by the reaction of uranium dissolved in a liquid zinc-magnesium alloy with finely divided carbon suspended in the liquid-metal solution. The carbide precipitated as an insoluble solid phase that was heavier than the solvent metal. After a settling period, the bulk of the Zn-Mg supernatant liquid was transferred by pressure-siphoning. The Zn-Mg remaining with the UC precipitate was removed by vacuum distillation at temperatures of 850 to 900°C. The better UC products had a carbon-to-uranium atom ratio (C/U) of 1.05 to 1.10 and contained 0.2 to 0.3 wt% O and 0.2 to 0.4 wt% Mg and Zn. Uranium monocarbide was the only compound formed by this method but it was not possible to produce UC with a C/U ratio of 1.00 or less because an excess of carbon was necessary to completely react the dissolved uranium.