On the chemical transport of some niobium oxides with TeCl4 (II). The transport behaviour of the equilibrium NbO2.417 to NbO2.5

A report is given on the transport behaviour of the equilibrium phases NbO_2.417 to NbO_2.483 and of niobium pentoxide during chemical transport with TeCl₄. – It became apparent that phase-pure NbO_2.417 and Nb₂O₅ are deposited from the investigated equilibrium phases. Chemical transport of the phases NbO_2.453 to NbO_2.483 produces a mixture of several phases. This indicates a strong inhibition of the equilibration in the starting solid. Chemical transport of the niobium pentoxide caused the deposition of monocrystals of the upper and lower phase boundary. The experimental behaviour agrees very well with the calculated results. Monocrystals of the niobium pentoxide forms H, M, N, B and P are deposited in a well identifiable manner by variation of the temperatures (T₂, T₁).