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  2. List of character tables for chemically important 3D point groups

    en.wikipedia.org/wiki/List_of_character_tables...

    These groups are characterized by i) an n-fold proper rotation axis C n; ii) n 2-fold proper rotation axes C 2 normal to C n; iii) a mirror plane σ h normal to C n and containing the C 2 s. The D 1h group is the same as the C 2v group in the pyramidal groups section. The D 8h table reflects the 2007 discovery of errors in older references. [4]

  3. Isoelectronicity - Wikipedia

    en.wikipedia.org/wiki/Isoelectronicity

    Molecular orbital diagrams best illustrate isoelectronicity in diatomic molecules, showing how atomic orbital mixing in isoelectronic species results in identical orbital combination, and thus also bonding. More complex molecules can be polyatomic also. For example, the amino acids serine, cysteine, and selenocysteine are all isoelectronic to ...

  4. Group (periodic table) - Wikipedia

    en.wikipedia.org/wiki/Group_(periodic_table)

    In the periodic table of the elements, each column is a group. In chemistry, a group (also known as a family) [1] is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the 14 f-block columns, between groups 2 and 3, are not numbered.

  5. Zintl phase - Wikipedia

    en.wikipedia.org/wiki/Zintl_phase

    Zintl phases are intermetallic compounds that have a pronounced ionic bonding character. They are made up of a polyanionic substructure and group 1 or 2 counter ions, and their structure can be understood by a formal electron transfer from the electropositive element to the more electronegative element in their composition.

  6. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    The f-block groups are ignored in this numbering. [22] Groups can also be named by their first element, e.g. the "scandium group" for group 3. [22] Previously, groups were known by Roman numerals. In the United States, the Roman numerals were followed by either an "A" if the group was in the s-or p-block, or a "B" if the group was in the d-block.

  7. Isolobal principle - Wikipedia

    en.wikipedia.org/wiki/Isolobal_principle

    Isolobal compounds are analogues to isoelectronic compounds that share the same number of valence electrons and structure. A graphic representation of isolobal structures, with the isolobal pairs connected through a double-headed arrow with half an orbital below, is found in Figure 1. Figure 1: Basic example of the isolobal analogy

  8. Functional group - Wikipedia

    en.wikipedia.org/wiki/Functional_group

    The reactivity of a functional group can be modified by other functional groups nearby. Functional group interconversion can be used in retrosynthetic analysis to plan organic synthesis. A functional group is a group of atoms in a molecule with distinctive chemical properties, regardless of the other atoms in the molecule.

  9. Infrared spectroscopy correlation table - Wikipedia

    en.wikipedia.org/wiki/Infrared_spectroscopy...

    An infrared spectroscopy correlation table (or table of infrared absorption frequencies) is a list of absorption peaks and frequencies, typically reported in wavenumber, for common types of molecular bonds and functional groups.