Group III metals

All the elements discussed so far, except hydrogen, have been metals. Group III contains one element, boron, that is not a metal. The elements of Group III are ... 

Early transition metal, group III, and lanthanide catalysts 504... 

The experimentally measured specific heat of metal group III nitrides and the phonon determined specific heat for several chosen Debye temperatures are presented in FIGURE 1. 

Aluminium and its Congeners, including the Rare Earth Metals (Group III, of the Periodic Table). By H F V. Little, B.So. (Lond.), A.RC.S, Chief Chemist to Thorium, Ltd. 

The exchange and reduction chemistry is particularly prevalent in the early transition metals (groups III-VII). Some examples are shown in Eqs. (49-51) [150-152]. Along with / -elimination, these deleterious reactions are the major reason for poor to moderate yields (20-60%) in early transition metal chemistry. It has been suggested that MgX2 acts as a Lewis acid site that will promote the reduction of the transition metal s oxidation state... 

Organometallic compounds (s. a. under individual metals. Group III element. . ., Group IV —. . ., Group V —. . ., Metal carbonyls. Metal complex compounds, organo-. Reagents, organometallic)... 

Michael Springborg Introduction Model systems Alkali metals Group III elements Group IV elements AB semiconductors Gold... 

Wallace C H 1998 The rapid solid-state synthesis of group III and transition metal nitrides at ambient and high pressures PhD Dissertation University of California, Los Angeles... 

This is an exothermic process, due largely to the large hydration enthalpy of the proton. However, unlike the metallic elements, non-metallic elements do not usually form hydrated cations when their compounds dissolve in water the process of hydrolysis occurs instead. The reason is probably to be found in the difference in ionisation energies. Compare boron and aluminium in Group III ... 

A non-metal or weakly electropositive metal X in Group III of the periodic table would be expeeted to form a covalent volatile hydride XHj. In fact, the simplest hydride of boron is BjHf, and aluminium hydride is a polymer (AlHj) . 

Of the five Group III elements, only boron and aluminium are reasonably familiar elements. Aluminium is in fact the most abundant metal, the third most abundant element in nature, but the other elements are rare and boron is the only one so far found In concentrated deposits. 

The data in Table 7.1 show that, as expected, density, ionic radius, and atomic radius increase with increasing atomic number. However, we should also note the marked differences in m.p. and liquid range of boron compared with the other Group III elements here we have the first indication of the very large difference in properties between boron and the other elements in the group. Boron is in fact a non-metal, whilst the remaining elements are metals with closely related properties. 

In the absence of oxygen, gallium and indium are unaffected by water. Thallium, the most metallic element in Group III, reacts slowly with hot water and readily with steam to produce thallium(I) oxide, TI2O. 

Two areas of passivity are located in Fig. 2-2 where Fe has a very low corrosion rate. In contrast to cathodically protected metals in groups I and II, the corrosion rate of anodically passivated metals in groups III and IV cannot in principle be zero. In most cases the systems belong to group IV where intensified weight loss corrosion or local corrosion occurs when U > U" There are only a few metals belonging to group III e.g., Ti, Zr [44] and A1 in neutral waters free of halides. 

By way of example, Volume 26 in Group III (Crystal and Solid State Physics) is devoted to Diffusion in Solid Metals and Alloys, this volume has an editor and 14 contributors. Their task was not only to gather numerical data on such matters as self- and chemical diffusivities, pressure dependence of diffusivities, diffusion along dislocations, surface diffusion, but also to exercise their professional judgment as to the reliability of the various numerical values available. The whole volume of about 750 pages is introduced by a chapter describing diffusion mechanisms and methods of measuring diffusivities this kind of introduction is a special feature of Landolt-Bornstein . Subsequent developments in diffusion data can then be found in a specialised journal. Defect and Diffusion Forum, which is not connected with Landolt-Bdrnstein. 

Relatively little work has been carried out on the derivatives of the metals of Group III, but (trimethyltin)lithium has been shown to react with the trialkylmetallic compounds RgM (M = B, Al, Ga, In, or Tl) to give the products MesSnMRs Li", which decompose (B immediately, Ga and Zn in two days) to give (MesSnljSnLi (279). 

Tables 1 to 5 summarize the sintering eharaeteristies of borides of groups III A to VIA transition metals.

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