Binary trivalent

An interesting feature of the binary, trivalent silyl-amides is the way that they pack in the crystalline lattice. 

The structure of this unique uranium (III) derivative is of much interest. Unfortunately we have been unable to obtain crystals satisfactory for an X-ray analysis. The compound is most likely similar to that of the binary, trivalent lanthanide derivatives, e.g., pyramidal rather than planar, on the basis of infrared spectroscopy. Planar M[N(SiMe3)2]3 show bands due to vas MNSi2 at 900 cm 1 whereas pyramidal ones absorb at 990 cm l. Since U[N(SiMe3)213 has its vas UNSi2 absorption band at 990 cm - - it is most likely pyramidal in the solid state. Not surprisingly the analogous thorium (III) derivative cannot be prepared in a similar fashion. 

In such systems as (M, Mj (i/2))X (M, monovalent cation Mj, divalent cation X, common anion), the much stronger interaction of M2 with X leads to restricted internal mobility of Mi. This is called the tranquilization effect by M2 on the internal mobility of Mi. This effect is clear when Mj is a divalent or trivalent cation. However, it also occurs in binary alkali systems such as (Na, K)OH. The isotherms belong to type II (Fig. 2) % decreases with increasing concentration of Na. Since the ionic radius of OH-is as small as F", the Coulombic attraction of Na-OH is considerably stronger than that of K-OH. 

Physical properties of binary or ternary Ru/Ir based mixed oxides with valve metal additions is still a field which deserves further research. The complexity of this matter has been demonstrated by Triggs [49] on (Ru,Ti)Ox who has shown, using XPS and other techniques (UPS, Mossbauer, Absorption, Conductivity), that Ru in TiOz (Ti rich phase) adopts different valence states depending on the environment. Possible donors or acceptors are compensated by Ru in the respective valence state. Trivalent donors are compensated by Ru5+, pentavalent acceptors will be compensated by Ru3+ or even Ru2+. In pure TiOz ruthenium adopts the tetravalent state. The surface composition of the titanium rich phase (2% Ru) was found to be identical to the nominal composition. 

Figure 4.16. Rare earth-magnesium binary systems. A few selected diagrams of trivalent lanthanides are shown. Notice the progressive regular changes on passing from the light to the heavy lanthanides. Notice also the similarity of the Y-Mg diagram with those of the heavy lanthanides.

Figure 5.14. Compound formation capability in the binary alloys of Sc, Y, light trivalent lanthanides (as exemplified by La), heavy trivalent lanthanides (exemplified by Gd) and of the actinides (exemplified by Th, U and Pu). The different partners of the 3rd group metals are identified by their position in the Periodic Table. Notice that a sharper subdivision between compound-forming and not forming metals will result from a shifting of Be and Mg from their position in the 2nd group towards the 12th group (see 5.12.3). The behaviour of the divalent lanthanides Eu and Yb is shown in Fig. 5.7 where it is compared with that of the alkaline earth metals.

The guest cations hitherto examined cover broadly uni- to trivalent and inorganic to organic ions that include alkali, alkaline earth, heavy and transition metal ions, as well as (ar)alkyl ammonium and diazonium ions. As to the complex stoichiometry between cation and ligand, both 1 1 stoichiometric and 1 2 sandwich complexes are analyzed. The solvent systems employed also vary widely from protic and aprotic homogeneous phase to binary-phase solvent extraction. 

Stibine. Sbl h, is formed by hydrolysis of some metal antimonides or reduction (with hydrogen produced by addition of zinc and HC1) of antimony compounds, as in the Gutzeit test. It is decomposed by aqueous bases, in contrast with arsine. It reacts with metals at higher temperatures to give the antimonides. The antimonides of elements of group la. 2a, and 3a usually are stoichiometric, with antimony trivalent. With other metals, the binary compounds are essentially intermetallic. with such exceptions as the nickel series, Ni. Sb.. NiSb, Ni5Sb2 and Ni4Sb. 

A new concept integrating both the PUREX and the TRPO processes is proposed by the INET researchers. This simplified PUREX-TRPO process uses a binary mixture of TBP (20%) and TRPO (20%) in kerosene to extract all actinides including TPEs, which can be back-extracted together with the trivalent lanthanides in a 5.5 M HN03 solution as in the TRPO process (94). 

Chlorostannate and chloroferrate [110] systems have been characterized but these metals are of little use for electrodeposition and hence no concerted studies have been made of their electrochemical properties. The electrochemical windows of the Lewis acidic mixtures of FeCh and SnCh have been characterized with ChCl (both in a 2 1 molar ratio) and it was found that the potential windows were similar to those predicted from the standard aqueous reduction potentials [110]. The ferric chloride system was studied by Katayama et al. for battery application [111], The redox reaction between divalent and trivalent iron species in binary and ternary molten salt systems consisting of 1-ethyl-3-methylimidazolium chloride ([EMIMJC1) with iron chlorides, FeCb and FeCl j, was investigated as possible half-cell reactions for novel rechargeable redox batteries. A reversible one-electron redox reaction was observed on a platinum electrode at 130 °C. 

CHEMISTRY OF THE TRIVALENT STATE BINARY COMPOUNDS 6-3 Oxygen Compounds... 

The -Alumina-related Structures.—Originally the compound )3-alumina was taken to be a binary aluminium oxide, but early Y-ray structure determinations and associated chemical analysis showed that the formula was approximately NaAlnOi7. Since then a number of isostructural compounds have been characterized in which sodium is replaced by other monovalent ions, particularly silver, and aluminium by other trivalent ions, notably gallium and iron. In addition, a number of other phases have been prepared which are structurally closely related to )8-alumina. Four principal structures are known, which are labelled / ", and P"". These can also be prepared with other monovalent cations replacing sodium, and some seem only to be formed when a few per cent of divalent cations, particularly magnesium, are present, so that they are, in fact, quaternary phases. The structure and stoicheiometry of these compounds has been summarized recently and we will only consider here those aspects relevant to the present topic. 

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