Chemical behavior of tungstate solutions. Part 1. A spectroscopic survey of the species involved.
This study is focused on the composition and the evolution of tungstate ions solutions as a function of pH and increasing concentrations. The Raman analysis showed that, during the titration of the tungstate solutions, WO4(2-), HWO4- ions and probably W2O7(2-) , HW2O7(2-) and H2W2O7 solvated species could exist in aqueous solutions. For diluted solutions, additions of a strong acid does not cause any precipitation, whereas the formation of the unstable solid tungstic acid (H2WO4 or WO3.H2O) could occur in concentrated solutions.
Barré
Thierry
T
Balzers Luxembourg, ZI Haanebesch, L-4513 Niedercom, Luxembourg.
Arurault
Laurent
L
Sauvage
François X
FX
D011232:Chemical Precipitation; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D008956:Models, Chemical; D009532:Nickel / Q000737:chemistry; D013053:Spectrophotometry; D013059:Spectrum Analysis, Raman / Q000379:methods*; D017973:Tungsten Compounds / Q000737:chemistry*
D007477:Ions; D017973:Tungsten Compounds; D009532:Nickel; D006859:Hydrogen; C021101:tungstic(VI) acid; C045951:tungstate