Synthesis and structural relationship of complex tantalum phosphates in the flux system K2O-P2O5-Ta2O5-MoO3

Abstract

Single crystals of K2Ta4O11 (I), K(TaO2)2PO4 (II) and K3Ta5O11(PO4)2 (III) were synthesized by flux-aided method in the pseudo-quaternary system K2O-P2O5-Ta2O5-MoO3. Tight interrelation of their crystal structures has been found via X-ray diffraction study. Experimental solid-state band gap measurements revealed its semiconductor nature corroborated with DFT calculations. Local structure of PO4 groups in (II) and (III) compounds was probed with ³¹P MAS NMR spectroscopy.