Definition

Noun: 1. The chemical element Hafnium: A lustrous, silvery-grey, tetravalent transition metal. It is chemically similar to zirconium and is found in zirconium minerals. It is used in control rods for nuclear reactors, in superalloys, and in filaments for its thermionic emission properties. * Scientific Context: In chemistry and materials science, "Hf" is the standard symbol for the element hafnium (atomic number 72).

Usage Examples

• Noun:
  • The alloy contained a small percentage of Hf to improve its high-temperature strength.
  • Hf has a high neutron absorption cross-section, making it useful in nuclear reactor control rods.
  • The mineral zircon often contains traces of Hf.

Advanced Usage

• In Scientific Notation: "Hf" is used in chemical formulas and periodic tables exclusively to represent the element hafnium. It is not used in general English prose.
  • The compound's formula was written as HfC, indicating hafnium carbide.

Variants and Related Words

• Hafnium (n): The full name of the element for which "Hf" is the symbol.
  • Hafnium is difficult to separate from zirconium due to their chemical similarity.

Synonyms

• Element 72: A descriptive synonym referencing its atomic number.
• Hafnium: The direct, full-name synonym.

Notes on Usage

• "Hf" is a specialized term. It is an initialism (chemical symbol) used almost exclusively in scientific, technical, and industrial contexts. It is not a standalone word in everyday English vocabulary.
• In the provided reference context, the frequency range "3 to 30 megahertz" describes the radio band "HF" (High Frequency), which is a different and unrelated initialism. The definition provided here is solely for "Hf" as the chemical element hafnium.

Noun

1. 3 to 30 megahertz
2. a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons