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  2. Lanthanide - Wikipedia

    en.wikipedia.org/wiki/Lanthanide

    All of the lanthanides form sesquioxides, Ln 2 O 3. The lighter/larger lanthanides adopt a hexagonal 7-coordinate structure while the heavier/smaller ones adopt a cubic 6-coordinate "C-M 2 O 3" structure. [50] All of the sesquioxides are basic, and absorb water and carbon dioxide from air to form carbonates, hydroxides and hydroxycarbonates. [57]

  3. Organolanthanide chemistry - Wikipedia

    en.wikipedia.org/wiki/Organolanthanide_chemistry

    Metal-carbon σ bonds are found in alkyls of the lanthanide elements such as [LnMe 6] 3− and Ln[CH(SiMe 3) 2] 3. [1] Methyllithium dissolved in THF reacts in stoichiometric ratio with LnCl 3 (Ln = Y, La) to yield Ln(CH 3) 3 probably contaminated with LiCl. Chemical structures of [LnMe6]3- and Ln[CH(SiMe3)2]3

  4. Lanthanide compounds - Wikipedia

    en.wikipedia.org/wiki/Lanthanide_compounds

    All of the lanthanides form sesquioxides, Ln 2 O 3. The lighter (larger) lanthanides adopt a hexagonal 7-coordinate structure while the heavier/smaller ones adopt a cubic 6-coordinate "C-M 2 O 3" structure. [11] All of the sesquioxides are basic, and absorb water and carbon dioxide from air to form carbonates, hydroxides and hydroxycarbonates. [7]

  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. Thorium compounds - Wikipedia

    en.wikipedia.org/wiki/Thorium_compounds

    It easily absorbs atmospheric carbon dioxide to form the hydrated carbonate ThOCO 3 ·xH 2 O and, under high-pressure conditions in a carbon dioxide atmosphere, Th(CO 3) 2 •½H 2 O or Th(OH) 2 CO 3 •2H 2 O. [13] [25] Several mixed oxides are known, such as BaThO 3, which has the perovskite structure. [22]

  7. Valence bond theory - Wikipedia

    en.wikipedia.org/wiki/Valence_bond_theory

    Valence bond theory complements molecular orbital theory, which does not adhere to the valence bond idea that electron pairs are localized between two specific atoms in a molecule but that they are distributed in sets of molecular orbitals which can extend over the entire molecule. Although both theories describe chemical bonding, molecular ...

  8. Unpaired electron - Wikipedia

    en.wikipedia.org/wiki/Unpaired_electron

    In chemistry, an unpaired electron is an electron that occupies an orbital of an atom singly, rather than as part of an electron pair. Each atomic orbital of an atom (specified by the three quantum numbers n, l and m) has a capacity to contain two electrons ( electron pair ) with opposite spins .

  9. Linear molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Linear_molecular_geometry

    Linear organic molecules, such as acetylene (HC≡CH), are often described by invoking sp orbital hybridization for their carbon centers. Two sp orbitals. According to the VSEPR model (Valence Shell Electron Pair Repulsion model), linear geometry occurs at central atoms with two bonded atoms and zero or three lone pairs (AX 2 or AX 2 E 3) in ...