Group IVB and VB elements

This method is applicable to a wide range of heavy metal and metalloid elements. Two conditions must be fulfilled for it to be applied successfully. First, as aqueous media are used, the product must not be susceptible to hydrolysis. This restricts its use to aryls of Hg, T1 and the Group IVB and VB elements. Secondly the element involved must be susceptible to electrophilic attack by the aryldiazonium ion ArN2"-. 

Se, Te, F, Cl, Br and I and R = H or alkyl groups, and have found that the spectra bear no simple relation to basicities, ionization potentials and other parameters. Recently, Rao and co-workers19 studied the absorption spectra of several polyphenyl derivatives of the elements of groups IVb and Vb. In the case of the Vb elements, the spectra of derivatives in which the atoms possess and do not possess unshared / -electrons (i.e. derivatives of the atoms in their trivalent and pentavalent states respectively) have been studied. The unshared / -electrons on the central atoms of the triphenyl derivatives of the Vb elements interact strongly with the r-orbitals of the benzene rings and the vibrational structure of the 260 m/x band of benzene is completely absent. 

The transfer of alkyl or aryl groups from one element to another may not necessarily be complete. Thus the aryls of Groups IVB and VB react with alkali metals in ether solvents or in liquid ammonia,... 

All elements that form isochains can also form heterochains with other elements. In addition, simple heterochains can sometimes be formed by the next higher row of the periods III, IVB, and VB, namely aluminum, iron, and bismuth. Compounds with multicenter bonds are also formed by beryllium and a few elements from higher rows, e.g., niobium and vanadium. In these compounds, as well as the OH and H groups, the elements of period VIIB can also occur as the central atoms in multicenter bridge bonding, that is, in borohydrides, niobium iodide, etc. These elements, however, do not represent true chain atoms. 

Fig. 14. Stress—rupture properties of NiAl alloys and composites compared with superaHoy Renit 80 (77). The Heusler precipitates (ppts) = 50 Ni—25 Al—25X (at. %), where X = a Group 4 (IVB) or Group 5 (VB) element such as Hf. To convert MPa to psi, multiply by 145.

The nitrides of Groups 4(IVB) and 5(VB) elements form at ca 1200°C. The nitrides of magnesium and aluminum form at 800°C. Aluminum nitride, obtained by beating aluminum powder in the presence of ammonia or nitrogen at 800—1000°C, is formed as a white to grayish blue powder. A grade of... 

Metallo-organics are compounds in which the atom of an element is bound to one or more carbon atoms of an organic hydrocarbon group. Many of the elements used in MOCVD are the metals of groups Ila, Ilb, Illb, IVb, Vb, and VIb, which are non-transitional. The metallo-organics thus complement the halides and carbonyls, which are the precursors for the deposition of transition metals (Groups IVa, Va, and Via) and their compounds. 

For the production of bodies containing c-BN and w-BN, the w-BN powder is mixed with various carbides from Group 4 or 5 (IVB, VB) elements, and afterwards the mixture is hot-pressed under high-temperature and high-pressure conditions. With this method a sintered workpiece containing w-BN and c-BN in a continuous binding phase is obtained [244]. 

Protonic acid cleavage of compounds containing nonmetal-N or metal-N bonds results in N—H bonds. These reactions produce amines that are more readily prepared by other reactions hence, they are of limited synthetic utility. Groups IIIB, IVB (except C), and VB (except N) element-N bond cleavage reactions are ... 

Oxides of Group Illb, IVb, Vb Elements and their Quasi-binaries with... 

Table 14. Summary of mass spectrometric studies of oxides of group Illb, IVb, Vb elements and their quasi-binaries with transition metals except those listed in Table 18. (The gaseous species or solid compounds are underlined if their enthalpies of formation or of dissociation, only gaseous species, are given)... 

Figure 4.3 Hydrogen flux through membranes of various thickness fabricated with Group IVB-VB elements. Data show that the rate limiting steps determining hydrogen flux vary and include diffusion through the bulk membrane material for the thicker membranes, gas phase diffusion at high pressures,...

The maximum oxidation state possible equals the number of i and d electrons in the valence shell (which equals the group number for the elements up to iron). Titanium in Group IVB has a maximum oxidation state of +4. Similarly, vanadium (Group VB), chromium (Group VIB), and manganese (Group VIIB) exhibit maximum oxidation states of +5, +6, and +7, respectively. ... 

Harrah, L. A., Ryan, M. T., Tamborski, C., Infrared Spectra of Phenyl Derivatives of Group IVb, Vb and VIIb Elements, Spectrochim. Acta 18 [1962] 21/37. 

Sigler D R (1989), Aluminum Oxide Adherence on Fe-Cr-Al Alloys Modified with Group IBB, IVB, VB and VIB Elements, Oxld Met, 32, 337-355. 

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