The U3Fe2C5 compound was prepared from the elements by arc-melting, followed by an heat-treatment in an induction furnace, at 1250°C for 1h and 1300°C for 2h. The crystal structure of this phase was determined by direct methods from single crystal X-ray diffraction data. U3Fe2C5 crystallizes in an original tetragonal crystal structure, with space group I4/mmm, a=3.4980(3)Å and c=19.8380(15)Å as lattice constants and two formula units per cell. This new type structure is characterized by the simultaneous presence of isolated and pairs of carbon atoms, the interatomic distances in the pairs being similar to a typical carbon–carbon double bond length found in a molecule. U3Fe2C5 is closely related to UC and UFeC2, and can be seen as build from two (distorted) UFeC2 unit cells and a UC layer.