摘要:

AbstractA new method has been developed for the preparation of methylmetal compounds from methyl chloride and the chlorides of boron, aluminum, silicon, tin, phosphorus, antimony, or mercury. Fused salts are used as solvents, and metals are suspended in these to act as halogen acceptors. The metals are recovered, together with chlorine, by electrolysis. This process, which can be carried out continuously and quantitatively, can be used for the preparation of technically important methylmetal compounds that cannot be obtained directly by the “Mülheim aluminum alkyl metho

ISSN:0570-0833    

DOI:10.1002/anie.196600011

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractThe paper describes the application and limitations of magnetic methods to the problems of free‐radical chemistry (detection and quantitative investigation of the free‐radical state, relationships between structure and free‐radical formation, “distribution” of the unpaired electron, detection of mesomeric C, O, N, P, As, and Sn radicals, g‐factors, triplet states, and hyperfine structure). The problem of the diradical is described, and the paper closes with a discussion of the “Se

ISSN:0570-0833    

DOI:10.1002/anie.196600061

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractThe partition equilibria of zirconium and hafnium thiocyanates between water and methyl isobutyl ketone have been studied under various conditions. Since the system shows extremely marked deviations from Nernst's distribution law, the two elements cannot be prepared in a very pure state by a simple multi‐stage partition. By the use of suitable additives and a new scheme of material flow, however, a continuous process using 23 mixer settlers has been developed, by means of which ZrO2containing less than 10 p.p.m. of HfO2and HfO2containing only 0.3% of ZrO2can be obtained from a zirconium‐hafnium mixture (hafnium content: 1 to

ISSN:0570-0833    

DOI:10.1002/anie.196600151

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractProtactinium exhibits an ambivalent chemical behavior. In non‐aqueous solutions and in the solid state, both quadrivalent and quinquevalent protactinium has properties which characterize it as a typical actinide element. On the other hand, investigations in aqueous solution show quinquevalent protactinium to be a homologue of niobium and tantalum. It exhibits – except in hydrofluoric acid solutions – a marked tendency to undergo irreversible hydrolysis and condensation reactions, which leads to the situation that tracer amounts (ca. 10−12mole/l) and macroscopic amounts (10−3–10−6mole/l) of protactinium often behave differently. Reduction with strong reducing agents gives aqueous solutions of Pa(IV), the properties of which again correspond in general to those of Th(IV) and show no relation to Nb(IV). Our knowledge of the chemical behavior of this rare radioelement has been advanced, in particular, by the production in 1958–1960 of 100 g of pure protactinium – the largest amount so far – from residues of the British pr

ISSN:0570-0833    

DOI:10.1002/anie.196600231

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractSome syntheses of heretofore unknown pyrimidines, tetrahydroquinazolines, and quinazolines are described. These methods are uniquely simple one‐ or two‐step reactions, general and versatile in scope, and give high yields. Some interesting chemistry associated with these heterocyclic systems is discus

ISSN:0570-0833    

DOI:10.1002/anie.196600351

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractNiobium pentoxide crystallizes in numerous modifications. The present paper describes their mode of formation, structures, and thermal properties.

ISSN:0570-0833    

DOI:10.1002/anie.196600401

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractThe formation and properties of silicon‐phosphorus and aluminum‐phosphorus compounds are described. Silylphosphines are decomposed solvolytically by H2O, C2H5OH, NH3, hydrogen halides, C2H5I, and boron halides at the SiP bond; decomposition may be preceded by formation of an addition compound. Extensive side reactions during the reaction of halogenosilanes with LiPEt2The following abbreviations are used in this paper: Et = C2H5; Me = CH3; M = alkali metal(formation of Et2PPEt2, HPEt2, Si‐rich residues) are due to an excess of LiPEt2in the reaction mixture. The reaction of LiPEt2with AlCl3, AlHCl2, and AlH2Cl leads to definite aluminum‐phosphorus compounds if only one PEt2group is present per Al atom, e.g. in (Cl2Al–PEt2)3, or if salts such as Li[Al(PEt2)4] and Li[AlH2(PEt2)2] can be formed with an exc

ISSN:0570-0833    

DOI:10.1002/anie.196600531

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractPhase and structural relationships of the sulfur, selenium, and tellurium compounds of the 4d and 5d transition elements of groups IV to VII of the periodic system are discussed. Homologous elements behave very similarly with respect to the chalcogens, and this is particularly the case for niobium and tantalum, and for molybdenum and tungsten. However, zirconium, niobium, and molybdenum have a greater tendency towards formation of chalcogen‐poor phases than their homologues hafnium, tantalum, and tungsten. Subchalcogenides are known only for zirconium and niobium. The number of phases and the tendency towards formation of solid solutions are considerably smaller among the tellurides than among the sulfides and selenides. The crystal structures of the telluride phases also differ from those of the sulfide and selenide phases of analogous composition. In addition, a review of the phase and structural relationships of the arsenic and antimony compounds of the 4d and 5d transition elements of groups V to VII is give

ISSN:0570-0833    

DOI:10.1002/anie.196600581

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractThe fundamentals of the theory of crystal growth comprise the two concepts of growth via two‐dimensional nuclei and growth with the aid of dislocations. Measurements of the relationship between rate of growth and supersaturation are particularly suitable for testing theoretical predictions. Experimental results are compared with predictions for crystal growth from the vapor phase, from solution, and from the melt. Depending on the experimental conditions, examples of both types of growth are met irrespective of the nature of the mother phas

ISSN:0570-0833    

DOI:10.1002/anie.196600671

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractSome recent examples of reactions proceeding both in the gas phase and in solution have been investigated to determine their kinetics and mechanisms. The ratio of the corresponding rate constants, kGand kL, of the elementary processes studied has been found to be about unity for unimolecular reactions and between 1 and 10 for bimolecular reactions. The mechanisms, overall rates, rate constants, and activation energies have been determined for the homogeneous gas reaction NOCl + Cl2O = NO2Cl + Cl2and the reaction NOCl + N2O5= NO2Cl + 2 NO2, carried out in C2F3Cl3.

ISSN:0570-0833    

DOI:10.1002/anie.196600781

出版商:Hüthig&Wepf Verlag    

年代:1966

数据来源: WILEY