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  2. Localized molecular orbitals - Wikipedia

    en.wikipedia.org/wiki/Localized_molecular_orbitals

    For instance, the lone pairs of water are usually treated as two equivalent sp x hybrid orbitals, while the corresponding "nonbonding" orbitals of carbenes are generally treated as a filled σ(out) orbital and an unfilled pure p orbital, even though the lone pairs of water could be described analogously by filled σ(out) and p orbitals (for ...

  3. Lanthanide - Wikipedia

    en.wikipedia.org/wiki/Lanthanide

    The colors of the γ-sesquisulfides are La 2 S 3, white/yellow; Ce 2 S 3, dark red; Pr 2 S 3, green; Nd 2 S 3, light green; Gd 2 S 3, sand; Tb 2 S 3, light yellow and Dy 2 S 3, orange. [60] The shade of γ-Ce 2 S 3 can be varied by doping with Na or Ca with hues ranging from dark red to yellow, [ 49 ] [ 60 ] and Ce 2 S 3 based pigments are used ...

  4. Organolanthanide chemistry - Wikipedia

    en.wikipedia.org/wiki/Organolanthanide_chemistry

    The lanthanide ions in these complexes can readily react with oxygen and water, leading to oxidation or hydrolysis, which damages the material’s structure and reduces its efficiency. This makes handling and storage difficult, requiring protective environments like sealed containers or inert gas atmospheres.

  5. 18-electron rule - Wikipedia

    en.wikipedia.org/wiki/18-electron_rule

    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 ns orbital, and three np orbitals, where n is the principal quantum number. These orbitals can collectively accommodate 18 electrons as either bonding or non-bonding electron pairs.

  6. Lanthanide compounds - Wikipedia

    en.wikipedia.org/wiki/Lanthanide_compounds

    Lanthanide metals react exothermically with hydrogen to form LnH 2, dihydrides. [1] With the exception of Eu and Yb, which resemble the Ba and Ca hydrides (non-conducting, transparent salt-like compounds),they form black pyrophoric, conducting compounds [6] where the metal sub-lattice is face centred cubic and the H atoms occupy tetrahedral sites. [1]

  7. Azimuthal quantum number - Wikipedia

    en.wikipedia.org/wiki/Azimuthal_quantum_number

    This is because the third quantum number m (which can be thought of loosely as the quantized projection of the angular momentum vector on the z-axis) runs from − to in integer units, and so there are 2ℓ + 1 possible states. Each distinct n, , m orbital can be occupied by two electrons with opposing spins (given by the ...

  8. Core electron - Wikipedia

    en.wikipedia.org/wiki/Core_electron

    For transition metals, the number of valence electrons ranges from 3 to 12 (ns and (n−1)d orbitals). For lanthanides and actinides, the number of valence electrons ranges from 3 to 16 (ns, (n−2)f and (n−1)d orbitals). All other non-valence electrons for an atom of that element are considered core electrons.

  9. Spin–orbit interaction - Wikipedia

    en.wikipedia.org/wiki/Spin–orbit_interaction

    Fine and hyperfine structure in hydrogen (not to scale). This section presents a relatively simple and quantitative description of the spin–orbit interaction for an electron bound to a hydrogen-like atom, up to first order in perturbation theory, using some semiclassical electrodynamics and non-relativistic quantum mechanics.