Abstract: Different types of organo--uranium compounds are synthesized to find onewhose volatility might be suitable for ~(235)U--enrichment. The compounds studiedinclude chelates of uranium with β--diketones, uranium alkoxy--compounds, coordina--tion compounds of uranium with crown ethers, sandwich complexes of uraniumand uranium amides. Some of the properties of the compounds studied are given,and the method of synthesis of ~(235)U--chelates with β--diketone is described in detail.