A general synthetic procedure for heteropolyniobates.
The heteropolyanions of W, Mo, and V, which have found numerous applications, are formed simply by acidification of solutions of their oxoanions. Under similar conditions, these oxoanion precursors are not available for Nb, and Nb-oxo chemistry is dominated by formation of the Lindquist ion [Nb6O19]8- only. However, heteropolyniobate formation is favored in hydrothermal reactions of aqueous, alkaline precursor mixtures. Here we give two examples of heteropolyniobates formed by this general reaction type: K12[Ti2O2][SiNb12O40].16H2O [1], which contains chains of silicododecaniobate Keggin ions, and Na14[H2Si4Nb16O56].45.5H2O [2], a new heteropolyanion structure type.
Nyman
May
M
Sandia National Laboratories, Albuquerque, NM 87185, USA. mdnyman@sandia.gov
Bonhomme
François
F
Alam
Todd M
TM
Rodriguez
Mark A
MA
Cherry
Brian R
BR
Krumhansl
James L
JL
Nenoff
Tina M
TM
Sattler
Amy M
AM