Definition

1. Noun:
   • A chemical element belonging to the lanthanide series: A lanthanide is any of a series of 15 metallic chemical elements with atomic numbers 57 through 71. They are known for their similar chemical properties, high density, and typically shiny, silvery-white appearance. They are often found together in mineral deposits.

Usage

• The term lanthanide is used primarily in scientific contexts, specifically in chemistry, geology, and materials science.
• It functions as a countable noun (e.g., , ).
• It is often used attributively as a noun modifier (e.g., , ).

Examples

• Noun:
  • Europium is a lanthanide used in the phosphors of television screens.
  • The lanthanides are sometimes called the rare-earth elements.
  • Scientists are studying the magnetic properties of this particular lanthanide.

Advanced Usage

• "Lanthanide contraction": A phenomenon in chemistry where the atomic radii of the lanthanide elements decrease more than expected across the series, influencing the properties of subsequent elements in the periodic table.
  • The lanthanide contraction explains the similar sizes of zirconium and hafnium.

Variants and Related Words

• Lanthanoid (noun): A synonym for lanthanide, often preferred in IUPAC nomenclature.
• Rare-earth element (noun): A broader category that includes the lanthanides plus scandium and yttrium. While not perfectly synonymous, the terms are often used interchangeably in non-technical contexts.

Synonyms

• Rare-earth element (in broad, non-technical usage)
• Lanthanoid

Related Phrases and Terms

• Lanthanide series (noun phrase): The specific group of 15 consecutive elements in the periodic table to which lanthanides belong.
  • The lanthanide series spans from lanthanum to lutetium.
• Inner transition metal (noun phrase): A category of metallic elements that includes both the lanthanide and actinide series.

Noun

1. any element of the lanthanide series (atomic numbers 57 through 71)