Polymeric Precursor Synthesis of the Superconducting Metal Boronitride La3Ni2B2N3

An efficient synthetic route to the superconducting La3Ni2B2N3 intermetallic has been developed based on the 1000 °C pyrolysis of lanthanum and nickel powders in polyborazylene, [B3N3H∼4]x. Elemental analyses, powder X-ray diffraction spectra, and ac susceptibility measurements confirm the formation of La3Ni2B2N3. This synthetic approach appears to be a general method for the preparation of a range of lanthanum metal boronitrides as is evidenced by its application to the synthesis of the previously unknown, nonsuperconducting La3Co2B2N3.