By H.J. Emeléus (ed.), A.G. Sharpe (ed.)
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Uneven synthesis continues to be a problem to training scientists because the want for enantiomerically natural or enriched compounds keeps to extend. over the past decade, a large number of literature has been released during this box. rules and purposes of uneven Synthesis consolidates and evaluates the main invaluable methodologies right into a one-volume source for the ease of practising scientists and scholars.
The hydrocarbons -- Alcohols and phytosterols -- Aldehydes and ketones -- Carboxylic acids -- The esters -- The lactones -- Anhydrides -- Carbohydrates and their derivatives -- Phenols and quinones -- The ethers -- Nitriles -- Acyclic amines -- Amides -- Imides -- N-nitrosamines -- Nitroalkanes, nitroarenes, and nitrophenols -- Nitrogen heterocyclic parts -- Miscellaneous elements -- fastened and variable gases -- steel and nonmetallic components, isotopes, ions, and salts -- insecticides and progress regulators -- Genes, nucleotides, and enzymes -- ''Hoffmann analytes'' -- Tobacco and/or tobacco smoke elements used as tobacco elements -- Pryolysis -- cancer agents, tumorigens, and mutagens vs.
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Extra resources for Advances in Inorganic Chemistry and Radiochemistry, Vol. 12
18 D. BROWN Reduction of the pentabromide by hydrogen, or better, aluminum at 400°C results in the formation of protactinium tetrabromide (44, 4 6 ) . I n the presence of excess aluminum no evidence for a lower oxidation state has been found. No second crystal form analogous to /3-ThBr4has been recorded. Like PaCl,, it can be sublimed above 5OOOC in vacuo with little decomposition. It reacts with antimony sesquioxide to form the orange oxydibromide, PaOBr,, which is isostructural with other tetravalent actinide oxydibromides (17, 4 4 ) .
It is a white, air-stable solid which decomposes to another, as yet unidentified, oxyfluoride at 45Oo-47O0C which, in turn, decomposes to PazO, above 65OOC. ) by metathesis of PaCI, using liquid boron tribromide and the first information on the heats of solution of tetravalent protactinium halides and oxydihalides (Fuger and Brown). I n addition, Weigel et al. 65 kcal molep1. ). 60, respectively (Fig. 10. Coordination around the protactinium atom in NaaPaFs. the sodium atoms are located between the PaFg- cubes.
Miscellaneous Compounds The remaining compounds of protactinium are more conveniently dealt with together since they belong to several different classes. Protactinium metal reacts with hydrogen to form the black hydride, PaH,, which is isostructural with other actinide trihydrides; it has only been prepared in submilligram amounts and identified by X-ray powder diffraction analysis (125). No binary sulfide has been reported, but the bright yellow oxysulfide, PaOS, isostructural with other actinide oxysulfides, has been obtained (125)by heating protactinium pentachloride or pentoxide in a mixture of carbon disulfide and hydrogen sulfide a t 900' and lZOO'C, respectively RECENT PREPARATIVE CHEMISTRY O F PROTACTINIUM 43 (Table XIV).