Structure and Cu++ EPR of γ'-Pb3V2O8

Solid-state reaction of PbO and V2O5 at 838 K yields a new room temperature γ' phase or Pb3V2O8. It is rhombohedral with lattice parameters a = 0.7500 nm α = 44.480, to be compared with a = 0.756 nm, α = 44.780 for the high temperature (T > 360 K) γ-phase. The EPR spectrum of a Cu(II)-doped γ'-phase exhibits an axially symmetric g-factor at 298 and 473 K that becomes nearly isotropic at 373 K. An endothermic DSC peak occurs at 368 and 371 K for the undoped and Cu-doped phases, respectively. The photoacoustic spectrum of the latter shows a broad peak at 690 nm. (author)