Definition

Noun: A soluble, inorganic compound of calcium, hydrogen, carbon, and oxygen (Ca(HCO₃)₂), formed when carbon dioxide dissolves in water containing calcium carbonate. It is a major cause of temporary water hardness.

Usage

This term is used primarily in scientific, technical, and domestic contexts to describe a specific chemical compound found in water. - It is the chemical form in which calcium is often transported in natural water systems like rivers and groundwater. - In domestic settings, it is discussed as the component in "hard water" that can form scale (limescale) inside pipes, kettles, and appliances when heated.

Examples

• Scientific Context:

  • The dissolution of limestone leads to the formation of calcium bicarbonate in groundwater.
  • When water containing calcium bicarbonate is boiled, carbon dioxide is driven off and calcium carbonate precipitates as scale.

• Domestic/Technical Context:

  • The white deposits in your kettle are caused by the breakdown of calcium bicarbonate in the tap water.
  • Temporary water hardness is due primarily to the presence of calcium bicarbonate.

Advanced Usage

• Geochemical Cycle: In earth sciences, calcium bicarbonate is a key intermediate in the carbonate cycle, facilitating the weathering of rocks and the transport of calcium to the oceans.
• Water Treatment: The process of removing calcium bicarbonate to soften water is often called "decarbonization" or "lime softening."

Variants and Related Words

• Bicarbonate (noun): The anion HCO₃⁻; a salt containing this anion.
• Calcium Carbonate (noun): The insoluble compound (CaCO₃) from which calcium bicarbonate forms and into which it decomposes.
• Temporary Hardness (noun phrase): The type of water hardness caused by dissolved calcium bicarbonate and magnesium bicarbonate, which can be removed by boiling.

Synonyms

• Calcium hydrogen carbonate (noun): The systematic IUPAC name for the same compound.

Related Phrases

• In solution: Calcium bicarbonate exists only in aqueous solution; it cannot be isolated as a pure solid.
• Cause of scale: A common phrase describing its primary practical effect in engineering and domestic contexts.

Noun

1. a bicarbonate that is a major cause of hard water