Definition

1. Noun:
   • A chemical element: Lanthanum is a soft, silvery-white, malleable, and ductile metallic element that tarnishes when exposed to air. It is the first element in the lanthanide series on the periodic table, with the atomic number 57 and symbol La. It is often found in combination with other rare-earth elements in minerals.

Usage Examples

• Noun:
  • Lanthanum is used in the production of camera and telescope lenses.
  • The chemist analyzed a sample containing lanthanum and cerium.
  • Lanthanum compounds are important catalysts in petroleum refining.

Advanced Usage

• Technical/Industrial Context: Lanthanum is frequently discussed in materials science, chemistry, and electronics for its specific properties.
  • The alloy's properties were enhanced by the addition of a small percentage of lanthanum.
  • Lanthanum oxide is a key component in certain types of optical glass.

Variants and Related Words

• Lanthanide (noun): Any of the series of 15 metallic elements from lanthanum (atomic number 57) to lutetium (atomic number 71) in the periodic table.
  • Neodymium and europium are other well-known lanthanides.
• Lanthanum oxide (noun): A white inorganic compound (La₂O₃) used in glass manufacturing and as a catalyst.
• Lanthanum carbonate (noun): A pharmaceutical compound used as a phosphate binder.

Synonyms

• Element 57: Referring to its atomic number.
• Rare-earth metal: A classification group that includes lanthanum, though technically it is one of the more abundant rare earths.

Related Phrases/Compounds

• Lanthanum series: Another term for the lanthanide series of elements.
• Lanthanum hexaboride (LaB₆): A compound used as a high-efficiency electron emitter in electron microscopes.

Noun

1. a white soft metallic element that tarnishes readily; occurs in rare earth minerals and is usually classified as a rare earth