lanthanide

(noun)

Any of the 14 rare earth elements from cerium (or from lanthanum) to lutetium in the periodic table. Because their outermost orbitals are empty, they have very similar chemistry. Below them are the actinides.

Related Terms

(noun)

Any of the 14 rare earth elements from lanthanum to lutetium in the periodic table. Because their outermost orbitals are empty, they have very similar chemistry. Below them are the actinides.

Related Terms

Examples of lanthanide in the following topics:

  • Lanthanides and Actinides

    • Lanthanides and actinides are elements of the inner transition series of the periodic table.
    • The 14 elements (numbers 58 to 71) of the lanthanide series are also known as the rare earth elements.
    • Most lanthanides are formed when uranium and plutonium undergo nuclear reactions.
    • This phenomenon is known as the lanthanide contraction.
    • All the lanthanide elements exhibit the oxidation state +3.

  • The Bottom of the Periodic Table

    • The atomic number that should be here, 57, is located at the bottom of the table in the row called the Lanthanides.
    • By expanding the horizontal dimensions of the table, the actinide and lanthanide rows can be put into their correct relative positions.
    • In 1934 only 4 actinides were known, all smaller than uranium, so it was not known that they formed a period or family like the lanthanides.
    • The actinides were added along with the lanthanides.
    • The lanthanides and actinides are added as separate but connected rows, building what is called the f-block.

  • Reactions of Coordination Compounds

    • Typically they either have low-charge (Na+), electrons in d orbitals that are antibonding with respect to the ligands (Zn2+), or lack covalency (Ln3+, where Ln is any lanthanide).

  • Diamagnetism and Paramagnetism

    • The size of the magnetic moment on a lanthanide atom can be quite large, as it can carry up to seven unpaired electrons, in the case of gadolinium(III) (hence its use in MRI).

  • The Periodic Table of Elements

    • Although groups generally have more significant periodic trends, there are regions where horizontal trends are more significant than vertical group trends, such as in the f-block, where the lanthanides and actinides form two substantial horizontal series of elements.

  • Coordination Number, Ligands, and Geometries

    • Due to their large size, lanthanides, actinides, and early transition metals tend to have high coordination numbers.

  • General Trends in Chemical Properties

    • The f block, usually offset below the rest of the periodic table, includes the lanthanides and actinides.

  • Variation of Physical Properties Across a Period

    • However, in the d-block, trends across periods become significant, and the f-block elements show a high degree of similarity across periods (particularly the lanthanides).

  • Fused Benzen Ring Compounds

    • Larger fullerenes are found to encapsulate lanthanide metal atoms.