Mooser-Pearson rule

As mentioned in the Introduction, no structural information on these species was available for more than 40 years after the discovery of the first Zintl metal cluster anions, since no pure crystalline phases could be isolated and characterized structurally. Nevertheless, early efforts to rationalize the observed formulas and chemical bonding of these intermetallics and related molecules utilized the Zintl-Klemm concept [75, 76] and the Mooser-Pearson [77] extended (8 — N) rule. In this rule N refers to the number of valence electrons of the more electronegative metal (and thus anionic metal) in the intermetallic phases. 

Early efforts to rationalize the observed formulas and chemical bonding of Zintl ions and related species used initially the Zintl-Klemm concept [10, 11] and subsequently the Mooser-Pearson [12] extended (8 — AO rule. In this rule, refers... 

The inherent basis of these procedures is the Zintl Kleimn concept and the Mooser-Pearson extended (8 — N) rule. Formerly applied only to classical two-center-two-electron bonds, the extended procedures comprise all varieties of bonding (multiple bonds, partial bonds, multicenter systems, radicals, and free electrons). Generally, for a compound AmB , an electron transfer A- -A +,... 

The inherent basis of these procedures is the Zintl-Klemm concept and the Mooser-Pearson extended (8 — N) rule. Formerly applied only to classical two-center-two-electron bonds, the extended procedures comprise all varieties of bonding (multiple bonds, partial bonds, multicenter systems, radicals, and free electrons). Generally, for a compound AmB , an electron transfer A- A +, B- mp = nq ) to the more electronegative element B forms pseudoelements k, B that show the structural principles of the corresponding isoelectronic elements with the whole spread of homoatomic bond types. Alternatively, one can derive from the number of valence electrons e and cb according to the equation otca + nee + k = 3n the term k = saa + Y. bb - e, which accounts for the... 

Several methods are available to analyze the electronic structure and discuss the chemical bonding of molecules and solids in a quantitative as well as qualitative way. Various levels of sophistication exist. From the chemist s perspective, electron counting schemes, such as the Zintl-Klemm (Klemm 1958 Schafer and Eisenmann 1981, von Schnering 1985), Mooser-Pearson (Mooser and Pearson 1956, 1960), or the (8 — N) rule (Kjekshus and Rakke 1974), which were frequently applied in the preceding section, are useful tools to understand relationships between composition and structure, structure and bonding, bonding and properties. Molecular orbital... 

The octet principle can be expressed as a formula by the generalized 8—N rule according to E. Mooser W. B. Pearson. We restrict our considerations to binary compounds, and presuppose the following ... 

The description of bonding within these compounds has been treated by several different approaches that come to the same conclusion. The (8 — N) rule that is generahzed by Mooser and Pearson uses a covalent model with collective counting of electrons. The generahzed 8 — N rule can be easily defined for simple binary compounds of the general formula, as 8x electrons are required in order... 

In addition to the reinterpretation of Pauling s rules developed by Burdett and McLarnan (1984), there have been a number of other studies related to various aspects of these standard rules. Due to the substantial number of errors in classifying AB compounds in terms of ionic radius ratio (e.g., Phillips, 1970 Tossell, 1980b), there have been numerous attempts to create structure maps that have two atomic quantities as coordinates and that can provide a unique separation of the different structure types. Such atom quantities may be related primarily to size or energy or to some combination of the two. Some of the most important such approaches are those of Mooser and Pearson (1959), Phillips (1970), and Simons and Bloch (1973). 

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