
%0 Journal Article
%A Smith, B. J. 
%A Patrick, V. A. 
%T Quantitative Determination of Sodium Dodecatungstosilicate Speciation by <emph type="7">183</emph>W Nuclear Magnetic Resonance Spectroscopy
%J Australian Journal of Chemistry
%D 2002/07/09
%V 55
%N 4
%P 281-286
%K 
%R https://doi.org/10.1071/CH01092
%U https://www.publish.csiro.au/paper/CH01092 
%X The speciation and equilibria of sodium dodecatungstosilicate has been determined using 183W nuclear magnetic resonance (NMR) spectroscopy over the pH range 3-13.5. The use of NMR allowed the direct observation of polytungstate anions in aqueous solution and at high concentration (0.5 mol L-1). Using this technique, the speciation of &#945;-[SiW12O40]4-, &#945;-[SiW11O39]8-, &#945;-[NaSiW11O39]7-, &#945;-[H2W12O40]6-, [H8W11O40]6-, [H7W11O40]7-, [W7O24]6-, [H2W12O42]10-, and WO42- was quantified as a function of pH. This work has allowed stability constants for &#945;-[SiW12O40]4- (log K 46) and &#945;-[SiW11O39]8- (log K 86) to be estimated. 
