Heat treatment of the sodium vanadium bronze NaV6O15 containing conducting
and plasticizing additives was found to yield compounds of vanadium in lowe
r oxidation states. The resulting phases were identified by x-ray diffracti
on analysis. A procedure is proposed for determining V3+, V4+, and V5+ coex
isting in mixed-phase materials. X-ray diffraction data correlate with anal
ytical results.