Ammonium metatungstate

Ammonium magnesium fluoride, 15 396 Ammonium metatungstates, 25 383 uses for, 25 388... 

Fig. 12. Quick EXAFS spectra measured during the sulfidation of Ni-W/A Os catalysts, during continuous heating of the catalyst in 5% FI2S in FI2 from room temperature to 673 K at 5 K/min and holding at 673 K for 30 min. The Ni-W03 catalyst was prepared from ammonium metatungstate, and the Ni-ATT catalyst was prepared from (NH4)2WS4.

WO surface density (W nm" ) Figure 2.10 Indirect absorption edge energies ofWO,-Zr02 samples at several oxidation temperatures and W loadings. Two crystalline W oxide materials (monoclinic WO3 and ammonium metatungstate) are shown for... 

Ammonium metatungstate crystallises in large, lustrous, tetragonal octahedra, with axial ratio a c=l 1-012, isomorphous with the potassium salt and with ammonium borotungstate, 5(NH4)20.B203. 24WO3.52H2O. The crystals, which are colourless and transparent,... 

A double compound of composition (XH4)o V40i3.XH4N0 j.2H20 separates on evaporating a solution containing ammonium metatungstate and excess of ammonium nitrate. It yields he.xagonal prisms which are decomposed by water. 

The alcohols used were 1-propanol and tert-butanol (with and without deuteration of the hydroxyl group) from Aldrich . The preparation of WZ (W content 6 wt%) is described elsewhere [2]. In brief, the catalyst is obtained by aqueous incipient wetness impregnation of hydrous zirconia with a solution containing the appropriate amount of ammonium metatungstate. The sample is subsequently calcined at 1096 K for one hour under flowing air. EXAFS measurements carried out at the National Synchrotron Light Source [7] showed that the WZ sample has an average W-O coordination number and distance of 4.7 and 1.69 A respectively. The surface area of the calcined material is 36 m /g. XRD reveals that a small amount of monoclinic zirconia was formed upon calcination. The Y-zeolite catalyst was... 

A1203 (Harshaw) impregnated with soln. of ammonium metatungstate, calcined at 500 C... 

For Ba2CoW06, the ammonium metatungstate could not be dissolved in the propionic acid, and was thus suspended in this acid before mixing. 

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