Definition

1. Noun:
   • An isotope of hydrogen: "Heavy hydrogen" is a stable isotope of hydrogen whose nucleus contains one proton and one neutron, giving it approximately twice the atomic mass of the most common hydrogen isotope. Its chemical symbol is D or ²H, and it is also called deuterium.

Usage

• "Heavy hydrogen" is used primarily in scientific and technical contexts, particularly in chemistry, nuclear physics, and engineering.
• It is a non-count noun. You refer to a quantity or sample of it (e.g., , ).
• It is often used attributively to modify other nouns (e.g., , which contains heavy hydrogen).

Examples

• Noun:
  • The reactor uses heavy hydrogen as a moderator.
  • Scientists can trace chemical pathways by substituting heavy hydrogen for ordinary hydrogen in molecules.
  • The difference in mass between hydrogen and heavy hydrogen affects reaction rates.

Advanced Usage

• "Deuterium": This is the standard scientific name for heavy hydrogen. The terms are synonymous in technical writing.
  • Deuterium, or heavy hydrogen, is crucial for nuclear fusion research.
• In compound form: It frequently appears in the term "heavy water" (D₂O), which is water where the hydrogen atoms are replaced by deuterium atoms.
  • Heavy water, containing heavy hydrogen, is used in some types of nuclear reactors.

Variants and Related Words

• Deuterium (n): The systematic name for heavy hydrogen (²H).
• Tritium (n): A radioactive isotope of hydrogen with two neutrons (³H). It is sometimes called "super-heavy hydrogen."
• Protium (n): The most common isotope of hydrogen, with no neutrons (¹H). This term is used to distinguish it from heavy hydrogen.
• Isotope (n): One of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons.

Synonyms

• Deuterium: The direct and more precise synonym.

Related Phrases and Compounds

• Heavy water: Water in which the hydrogen atoms are deuterium (heavy hydrogen) atoms.
  • The facility produces heavy water for industrial use.
• Deuterated compound: A chemical compound in which one or more hydrogen atoms have been replaced by deuterium (heavy hydrogen) atoms.
  • The deuterated solvent was analyzed using NMR spectroscopy.

Noun

1. an isotope of hydrogen which has one neutron (as opposed to zero neutrons in hydrogen)