Niobium nitride synthesis by pyrolysis of niobium pentachloride ammoniates

The conditions of preparing niobium nitride during thermal decomposition of niobium pentachloride ammoniates have been investigated. The synthesis of ammoniates has been realized in the course of interaction of NbCl4 powder with liquid ammonia at 210 K. At subsequent heating of ammoniates in the 650-1100 K temperature range the formation of nonsuperconducting cubic niobium nitride phase is observed. The heating up to 1300 deg C leads to phase transition with formation of hexagonal niobium nitride and above 1300 deg C of cubic niobium nitride with temperature of transition into super conducting state 12.6 K