Yttrium hydroxide

Gels of yttrium hydroxide are powerful catalysts for the hydrolysis of (76), and it was suggested that the hydroxide acts as a bifunctional general acid and nucleophile. The fact that gels of transition-metal hydroxides do not show comparable activity was attributed to their fixed co-ordination number, resulting in more rigid stereochemistry. 

Yttrium Thioarsenate.—Yttrium does not form an insoluble thioarsenate but, if yttrium hydroxide and arsenic pentasulphide are digested with wrater, thioarsenate is formed in solution. The compound is unstable, however, and gradually decomposes, with separation of sulphur and arsenic.5... 

Yttrium hydroxide. Y(OTT)3 is precipitated by NTI4OTT from solutions of yttrium salts. It differs in properties from the lanthanide hydroxides,... 

T. Curtius and A. Darapsky prepared a basic salt, lanthanum hydroxyazide, La(0H)(N3)2l H20, by boiling a soln. of lanthanum nitrate and sodium azide. The white, slimy mass of basic lanthanum azide is obtained by evaporating the mixed soln. in vacuo, or by treatment of the soln. with a mixture of alcohol and ether. They also made rose-coloured didymium hydroxyazide, Dy(OH)(N3)2, by evaporating a soln. of didymium carbonate in hydrazoic acid. Freshly precipitated yttrium hydroxide dissolves in hydrazoic acid, forming a soluble yttrium hydroxyazide boiling a soln. of yttrium sulphate and sodium azide gives a precipitate of yttrium hydroxide. L. M. Dennis found that zirconium hydroxide is precipitated when a soln. of zirconium salt is treated with potassium azide. 

MB6, M = Y, Gd, Tb, and Dy, which dissociate into MB4 and boron. Reaction of H2B12H12,6H20 with lanthanide, scandium or yttrium hydroxides or carbonates afforded40 M2(B12H12)3,xH20 (x = 15, 18, 20, or 21 depending on M) the compounds are ionic. 

FIGURE 8.6 The relative concentration of different zirconium, aluminum, magnesium, and yttrium hydroxide species as a function of pH at 25°C in 1.0 mol/dm aqueous solutions. (From Bergstrom, L., in Surface arid Colloid Chemistry in Advanced Ceramics Processing, R.J. Pugh and L. Bergstrom, Eds., Marcel Dekker, New York, 1994, 100-101. With permission.)... 

Zirconium and yttrium hydroxides were precipitated from solutions of ZrOCl2 and YCI3 using NH4OH. No precipitates were observed at n = 2 and below, where n is defined by the equation... 

EZH/ORL] Ezhova, Z. A., Orlovskii, V. P., Koval, E. M., Conditions of the coprecipitation of calcium hydroxyapatite with zirconium and yttrium hydroxides from aqueous solutions using ammonia, Russ. J. Inorg. Chem., 40, (1995), 1563-1566. Cited on page 341. 

T. Ikegami, J.G Li, T. Mori, Y. Moriyoshi, Fabrication of transparent yttria ceramics by the low-temperature synthesis of yttrium hydroxide. Journal of the American Ceramic Society, 85, 1725-9... 

After strontium carrier is added to a small volume (<10 ml) of °Sr solution, sufficient fuming nitric acid is added to attain a nitric acid concentration of 14-16 N. The solution with strontium nitrate precipitate is cooled in an ice bath and then centrifuged. The supernatant solution is thoroughly decanted and the strontium nitrate precipitate is dissolved in water. Barium and yttrium carriers are added. Precipitation of barium chromate at pH 5.5 removes and natural radium from the supernatant strontium solution (for counting, if needed, of these two separated radioelements). Precipitation of yttrium hydroxide in basic solution then removes the daughter that has grown into the °Sr parent. Ammonium oxalate is immediately added to the supernatant solution to precipitate strontium oxalate. The precipitate is washed and dried in the filter holder with alcohol and ether, promptly weighed for yield determination, and counted with a beta-particle detector (Chieco 1997) such as a proportional detector. 

An alternative is to store the supernatant solution after the barium chromate scavenging precipitation for 20 days until °Y approaches equilibrium with °Sr, and then precipitate yttrium hydroxide with the Y. The hydroxide is dissolved in dilute acid, and oxalic acid is added to precipitate yttrium oxalate. The precipitate is washed and dried, promptly weighed for yield determination, and counted with a proportional detector (Sunderman and Townley 1960). To the supernatant solution from the yttrium hydroxide precipitation, ammonium oxalate is added to precipitate strontium oxalate for weighing to determine the strontium yield. The °Sr activity is calculated from the °Y count rate adjusted for °Y ingrowth into the Sr parent, °Y decay since its separation from °Sr, yttrium and strontium yields, and °Y counting efficiency. 

Ikegami T, Mori T, Yajima Y, Takenouchi S, Misawa T, Moriyoshi Y (1999) Fabrication of transparent yttria ceramics through the synthesis of yttrium hydroxide at low temperamre and doping by sulfate ions. J Ceram Soc Jpn 107 297-299... 

Also, Berzelius observed that when working with yttrium oxide and adding ammonia to a solution of yttrium nitrate, precipitation takes place in the following sequence first, beryllium hydroxide is separated, and, subsequently, a yellowish substance mixed with the whitish yttrium hydroxide (Berzelius 1844b). 

Kovalenko, P.N. and Geiderovich, O. (1962) Determination of the pH of the beginning of dissolution and the product of solubility (activities) of yttrium hydroxide. Isvest. 

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