Hi Anubhab, not Nitrates (XNO3) but rather Nitrides (NbN). In common cases nitrides are as usable as the other variety of compound semiconductors as Nb3Sn, Nb3Ti, YBCO compound oxides, also MgB2 shoul be noted. So huge variety of compounds are used depending on the certain technical task. See
review material -https://arxiv.org/pdf/1502.04724.pdf See table 4 for some compounds.