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  2. Lanthanum - Wikipedia

    en.wikipedia.org/wiki/Lanthanum

    Lanthanum is a chemical element with the symbol La and the atomic number 57. It is a soft , ductile , silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table , of which lanthanum is the first and the prototype.

  3. Charge number - Wikipedia

    en.wikipedia.org/wiki/Charge_number

    In that case, the charge of an ion could be written as =. The charge number in chemistry normally relates to an electric charge. This is a property of specific subatomic atoms. These elements define the electromagnetic contact between the two elements. A chemical charge can be found by using the periodic table.

  4. Formal charge - Wikipedia

    en.wikipedia.org/wiki/Formal_charge

    Formal charges in ozone and the nitrate anion. In chemistry, a formal charge (F.C. or q*), in the covalent view of chemical bonding, is the hypothetical charge assigned to an atom in a molecule, assuming that electrons in all chemical bonds are shared equally between atoms, regardless of relative electronegativity.

  5. Lanthanide - Wikipedia

    en.wikipedia.org/wiki/Lanthanide

    All the trivalent lanthanide ions, except lanthanum and lutetium, have unpaired f electrons. (Ligand-to-metal charge transfer can nonetheless produce a nonzero f-occupancy even in La(III) compounds.) [81] However, the magnetic moments deviate considerably from the spin-only values because of strong spin–orbit coupling.

  6. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    General inorganic chemistry texts often put scandium (Sc), yttrium (Y), lanthanum (La), and actinium (Ac) in group 3, so that Ce–Lu and Th–Lr become the f-block between groups 3 and 4; this was based on incorrectly measured electron configurations from history, [25] and Lev Landau and Evgeny Lifshitz already considered it incorrect in 1948 ...

  7. Charge-transfer complex - Wikipedia

    en.wikipedia.org/wiki/Charge-transfer_complex

    In chemistry, charge-transfer (CT) complex, or electron donor-acceptor complex, describes a type of supramolecular assembly of two or more molecules or ions. The assembly consists of two molecules that self-attract through electrostatic forces, i.e., one has at least partial negative charge and the partner has partial positive charge, referred ...

  8. Chemical polarity - Wikipedia

    en.wikipedia.org/wiki/Chemical_polarity

    Two charges are present with a negative charge in the middle (red shade), and a positive charge at the ends (blue shade). In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end.

  9. Cyclopentadienyl complex - Wikipedia

    en.wikipedia.org/wiki/Cyclopentadienyl_complex

    All 5 carbon atoms of a Cp ligand are bound to the metal in the vast majority of M–Cp complexes. This bonding mode is called η 5-coordination.The M–Cp bonding arises from overlap of the five π molecular orbitals of the Cp ligand with the s, p, and d orbitals on the metal.