The langbeinite-type barium vanadium(III) orthophosphate, Ba3V4(PO4)6

Langbeinite-type Ba3V4(PO4)(6) has been crystallized from a stoichiometric melt starting from Ba(PO3)(2) and V2O3. The crystal structure has been refined from single-crystal X-ray diffraction data. It consists of a vanadato(III)-phosphate network [V-4(PO4)(6)](6-), which shows some resemblance to the NASICON structure type. A new method is presented for the visualization of this structural relationship. The single-crystal electronic spectrum of yellow-green Ba3V4(PO4)(6) shows the absorption bands typical for the octahedral chromophore [(VO6)-O-III].