Metallic halides, electronic configuration

Phosphoms shows a range of oxidation states from —3 to +5 by virtue of its electronic configuration. Elemental P is oxidized easily by nonmetals such as oxygen, sulfur, and halides to form compounds such as 2 5 2 5 reduced upon reaction with metals to generate phosphides. The... 

It must be emphasized that the duodectet rule (4.6) initially has no structural connotation, but is based on composition only. Indeed, the compositional regularity expressed by (4.6) encompasses both molecular species (such as the metal alkyls) and extended lattices (such as the oxides and halides) and therefore appears to transcend important structural classifications. Nevertheless, we expect (following Lewis) that such a rule of 12 may be associated with specific electronic configurations, bond connectivities, and geometrical propensities (perhaps quite different from those of octet-rule-conforming main-group atoms) that provide a useful qualitative model of the chemical and structural properties of transition metals. 

Zinc, cadmium and mercury are at the end of the transition series and have electron configurations ndw(n + l)s2 with filled d shells. They do not form any compound in which the d shell is other than full (unlike the metals Cu, Ag and Au of the preceding group) these metals therefore do not show the variable valence which is one of the characteristics of the transition metals. In this respect these metals are regarded as non-transition elements. They show, however, some resemblance to the d-metals for instance in their ability to form complexes (with NH3, amines, cyanide, halide ions, etc.). 

Chapter 6 is devoted to discussing the main optical properties of transition metal ions (3d" outer electronic configuration), trivalent rare earth ions (4f 5s 5p outer electronic configuration), and color centers, based on the concepts introduced in Chapter 5. These are the usual centers in solid state lasers and in various phosphors. In addition, these centers are very interesting from a didactic viewpoint. We introduce the Tanabe-Sugano and Dieke diagrams and their application to the interpretation of the main spectral features of transition metal ion and trivalent rare earth ion spectra, respectively. Color centers are also introduced in this chapter, special attention being devoted to the spectra of the simplest F centers in alkali halides. 

Nickel, heated gently in a stream of CO, forms the carbonyl Ni(CO)4. Carbonyls of other metals have been prepared by reduction of the halides with other metals in the presence of CO under high pressure. All carbonyls have 18-electron configurations the formulae of the carbonyls of metals with even atomic numbers thus can be easily found, e.g. Ni(CO)4, Fe(CO)5, Cr(CO)6 and Mo(CO)6. 

COLOR CENTERS. Certain crystals, such as the alkali halides, can be colored by the introduction of excess alkali metal into the lattice, or by irradiation with x-rays, energetic electrons, etc. Thus sodium chloride acquires a yellow color and potassium chloride a blue-violet color. The absorption spectra of such crystals have definite absorption bands throughout the ultraviolet, visible and near-infrared regions. The term color center is applied to special electronic configurations in the solid. The simplest and best understood of these color centers is the F center. Color centers are basically lattice defects that absorb light. 

Qualitative and quantitative aspects of the Lewis theory of acids and bases, and practical applications of Lewis acids, are discussed in a series of monographs [1,4-6,30-46] and reviews [47-49], The following aspects are taken into account (a) electronic configuration of acceptors (A = M MX are generally metal and boron salts), (b) nature of anions (usually halides), (c) peculiarities of thin structure of donors (B are generally the compounds containing N, P, As, Sb O, S, Se, Te F, Cl, Br, I atoms) their electronic structure, spatial accessibility, and mutual position of donor centers. Moreover, the nature of X, order of binding of A and B in formation of adducts of type AB , nature of solvents, and evaluation of AH or AG of the processes (1.1)—(1.5) [31,48] should also be considered. 

The platinum metals in the heavy series form especially inert hexahalo-complexes. Spectra for a number of these were reported by Jorgensen (14,15,16). A few of these which are illustrative of the effects of various ligands and of the electronic configurations have been reproduced in Figure 1. Usually, the solutions from which these spectra were obtained have contained excess halide ion to reduce any solvation effect. A number of limitations for the analytical and structural utility of the spectra are immediately evident from the spectra in Figure 1. First of... 

Answer (d) Element 114 falls below Pb in the Periodic Table. It should have the electron configuration [Rn] 5f " 6d °7s 7p. Chemically it should resemble lead. Its most stable oxidation state is likely to be 4-2, and compounds in the 4-4 state may be too unstable to exist at room temperature. It should form several compounds, including an oxide MO and several halides MX2 by analogy with lead, the chloride would be insoluble but a nitrate would be soluble. Element 114 could be a rather noble metal (though it has been suggested that the element might be a liquid or even a gas at room temperature ). 

Thus, the electronegativity values are linearly dependent on a parameter similar to the polarizing action of the cation. The dependence of the solubility on the Allred-Rochow electronegativity is divided into two sharply bounded and practically linear plots with close slopes for 3d-elements and for alkaline-earth metal-oxides (see Fig. 3.7.13). Since the slopes of these dependences are close, different positions of these plots may be explained by different relationships between the nuclear charge and Z for metals characterized by different electronic configurations. From the above-said it may be concluded that in high-temperature alkali-metal halide melts a correlation of metal-oxide solubilities with the crystal-lochemical radii of the cations is considerably simpler, i.e. it does not require the introduction of any corrections of the nucleus charge, such as Z. ... 

---