The experiment on the coherent dissociation of relativistic C-9 nuclei in a nuclear track emulsion is presented. Results include the charge topology and kinematical features of final states. Events of C-9 → 3 He-3 coherent dissociation are identified. Measurements are done with radioactive C-9 beams of energy 1.2 GeV/u produced at the Nuclotron akcelerator in Dubna.