Communication: The 2223 single-phase region in the Bi2O3-SrO-CaO-CuO system has been defined, enabling the preparation of pure (> 90%), unleaded Bi2Sr2Ca2Cu3O10. The bismuth content of the superconductor, which is better suited for research than the leaded variety, is found to be significantly higher (at 2.5) than expected from the exact stoichiometry. The preparation conditions and the phase diagram are discussed.