A new compound in the Nb–V–Sb–O system and its physicochemical characteristic

• The new ceramic compound of the formula Nb6VSb3O25 in the Nb–Sb–V–O system is formed.
• Nb6VSb3O25 is semiconductor, crystallizes in the orthorhombic system.
• Nb6VSb3O25 melts incongruently at 930 ± 5 °C.
• The solid product of melting of Nb6VSb3O25 is Nb9VO25.

A new compound of the formula Nb6VSb3O25 in the Nb–V–Sb–O system was characterized by the XRD, SEM/EDX, DTA–TGA, IR and UV–Vis–DR methods. The new compound was obtained in air atmosphere as a result of solid-state reaction between the oxides V2O5, Nb2O5 and Sb2O4 or Sb2O3, mixed at the molar ratio 1:6:3. Nb6VSb3O25 is a semiconductor with band gap energy 3.2 eV, crystallizes in the orthorhombic system, and melts incongruently at 930 ± 5 °C with deposition of solid Nb9VO25. The unit cell parameters of Nb6VSb3O25 were calculated and its IR spectrum was presented.