Transition element ions

Besides radical additions to unsaturated C—C bonds (Section III.B.l) and sulfene reactions (see above), sulfonyl halides are able to furnish sulfones by nucleophilic substitution of halide by appropriate C-nucleophiles. Undesired radical reactions are suppressed by avoiding heat, irradiation, radical initiators, transition-element ion catalysis, and unsuitable halogens. However, a second type of undesired reaction can occur by transfer of halogen instead of sulfonyl groups283-286 (which becomes the main reaction, e.g. with sulfuryl chloride). Normally, both types of undesired side-reaction can be avoided by utilizing sulfonyl fluorides. 

Table II I4I, 149-162) consists of a summary of 9-factors, D values and hyperfine coupling constants observed for ions of the first transition series. A molecular orbital (MO) treatment of the metal ion and ligand orbitals has been discussed by Stevens 163) and Owen 164) to account for covalent bonding and resulting hyperfine structure from hgands of transition element ions. Expressions derived for g-factors and hyperfine coupling constants from a MO treatment allow an estimation of the amount of charge transfer of metal electrons to ligand orbitals. Owen 164) has given a MO treatment of Cr +, Ni++ and Cu++ assuming no t bonding.

Crystal Field Theory (CFT) has also been used considerably to rationalize visible absorption spectra, hydration energies, stabilities of complexes, rates and mechanism of reaction, and redox potentials of transition element ions. These applications of CFT are summarized in a book by Basolo and Pearson 1B6). 

Ternary fluorides Cs2MeF4 on the other hand, containing the large cesium ions, are known of several transition element ions Me +. They crystallize in rhombohedral structures with large sizes of the unit cells z = 14) 8). Detailed information about the coordination of Me and Cs in these compounds is not yet available. 

The derivations of enthalpies of hydration of the transition element ions... 

Henderson, P. Dale, I. M. (1969) The partitioning of selected transition element ions between olivine and groundmass of oceanic basalts. Chem. Geol., 5,267-74. 

The coordination. Transition element ions are in general tetrahedrally or octahedrally coordinated. The ligand field is about twice lower for the fomfold coordination than for the sixfold one see Ligand Field Theory Spectra). The coordination number of lanthaiude ions varies from 6 to 12. The nephelauxetic effect and crystal field decrease with increasing coordination number. 

VARIABLE CHARGE NUMBERS OF TRANSITION ELEMENT IONS... 

Chemists must have a way to distinguish the names of compounds formed from the different ions of a transition element. They do this by using a Roman numeral to indicate the oxidation number of a transition element ion. This Roman numeral is placed in parentheses after the name of the element. No additional naming system is needed for zinc and silver compoimds because their formulas are not ambiguous. Table 5.3 shows the naming of the two different ionic compoimds formed when chloride ions combine with each of the two copper ions. 

Table 5.4 shows the chemical names of some transition element ions. When you do Practice Problems 5 and 6, you will become familiar with these names. Note in the photos accompanying the table that the different ions of a transition element often form compounds of different colors. 

This is in contrast to the tensor, where the principal value is positive. In Table IV, calculated values are given of the principal value of ( 22) for an electron in a p orbital for nontransition ions or the or d y orbitals for transition element ions, assuming the orbital contribution is fully quenched. The same problem concerning the use of (3cos 0 — 1) and (3cos 6 + 1) occurs, as it did for the p orbitals, but the magnitude of the principle values are unaffected. 

Transparent, polycrystalline MgAL04 spinel (TPSp) can be used in various applications, like rare-earth and transition element ion host, windows transparent in the visible (VIS) or near-infrared (NIR) domains, etc. ... 

Hydroxy- and 8-aminoquinolines form stable bidentate complexes with many transition element ions. Further enhancement of UVV absorbance can be attained by introduction of azo chromophores. 7-(2-Pyridylazo)-5-chloro-8-hydroxyquinohne (PACHQ, 21) yields a violet 2 1 hgand-to-Au(IIl) complex at pH 9.5 linearity range from 0 to... 

Actually very numerous transition elements ions containing coordination polymers have been described. Some of them are listed in table 1. 

Many highly colored substances contain transition-element ions. 

The transition element ions form complexes with a number of aromatic compounds in which two adjacent carbon atoms of the... 

Absorption of light is also possible by transfer of charges (electrons) from electron shells of one ion to unfilled shells of another ion located in sufficiently close spatial proximity. The spectral absorption bands resulting from such interionic transitions are sometimes called charge transfer bands. The participating ions may be major or minor components of the glass. Electron transfer between multivalent transition element ions, snch as Fe -Fe pairs, are examples of the latter. 

Aqueous solutions of transition element ions are hydrated. They are complex ions with water as a ligand. Different ligands form complexes with different stabilities. For example when we add concentrated aqueous ammonia to an aqueous solution of copper(II) sulfate, the ammonia ligands displace water ligands in a stepwise process. 

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