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  2. Polyhedral skeletal electron pair theory - Wikipedia

    en.wikipedia.org/wiki/Polyhedral_skeletal...

    In chemistry the polyhedral skeletal electron pair theory (PSEPT) provides electron counting rules useful for predicting the structures of clusters such as borane and carborane clusters. The electron counting rules were originally formulated by Kenneth Wade , [ 1 ] and were further developed by others including Michael Mingos ; [ 2 ] they are ...

  3. Zintl phase - Wikipedia

    en.wikipedia.org/wiki/Zintl_phase

    The geometry and bonding of a Zintl ion cannot be easily described by classical two electron two center bonding theories; however the geometries Zintl ions can be well described by Wade’s rules of boranes. Wade’s rules offer an alternative model for the relationship between geometry and electron count in delocalized electron deficient systems.

  4. Isolobal principle - Wikipedia

    en.wikipedia.org/wiki/Isolobal_principle

    In organometallic chemistry, the isolobal principle (more formally known as the isolobal analogy) is a strategy used to relate the structure of organic and inorganic molecular fragments in order to predict bonding properties of organometallic compounds. [1]

  5. Boron hydride clusters - Wikipedia

    en.wikipedia.org/wiki/Boron_hydride_clusters

    The International Union of Pure and Applied Chemistry rules for systematic naming is based on a prefix denoting a class of compound, followed by the number of boron atoms and finally the number of hydrogen atoms in parentheses. Various details can be omitted if there is no ambiguity about the meaning, for example, if only one structural type is ...

  6. Jemmis mno rules - Wikipedia

    en.wikipedia.org/wiki/Jemmis_mno_rules

    In chemistry, the Jemmis mno rules represent a unified rule for predicting and systematizing structures of compounds, usually clusters.The rules involve electron counting. They were formulated by E. D. Jemmis to explain the structures of condensed polyhedral boranes such as B 20 H 16, which are obtained by condensing polyhedral boranes by sharing a triangular face, an edge, a single vertex, or ...

  7. 18-electron rule - Wikipedia

    en.wikipedia.org/wiki/18-electron_rule

    The 18-electron rule is a chemical rule of thumb used primarily for predicting and rationalizing formulas for stable transition metal complexes, especially organometallic compounds. [1] The rule is based on the fact that the valence orbitals in the electron configuration of transition metals consist of five ( n −1)d orbitals, one n s orbital ...

  8. Inert-pair effect - Wikipedia

    en.wikipedia.org/wiki/Inert-pair_effect

    The inert-pair effect is the tendency of the two electrons in the outermost atomic s-orbital to remain unshared in compounds of post-transition metals.The term inert-pair effect is often used in relation to the increasing stability of oxidation states that are two less than the group valency for the heavier elements of groups 13, 14, 15 and 16.

  9. Fajans' rules - Wikipedia

    en.wikipedia.org/wiki/Fajans'_rules

    In inorganic chemistry, Fajans' rules, formulated by Kazimierz Fajans in 1923, [1] [2] [3] are used to predict whether a chemical bond will be covalent or ionic, and depend on the charge on the cation and the relative sizes of the cation and anion. They can be summarized in the following table: