Energy-rich species

In chemistry and particularly biochemistry, an energy-rich species (usually energy-rich molecule) or high-energy species (usually high-energy molecule) is a chemical species which reacts, potentially with other species found in the environment, to release chemical energy.^{[citation needed]}

In particular, the term is often used for:

• inorganic phosphate into the environment in an exothermic reaction with water
  :

ATP + H
₂O → ADP + P_i   ΔG°' = −30.5 kJ/mol (−7.3 kcal/mol)

• carbohydrates,^[5] lipids, proteins, and other organic molecules which react with oxygen in the environment to ultimately form carbon dioxide, water, and sometimes nitrogen, sulfates, and phosphates
• molecular hydrogen
• monatomic oxygen,^{[citation needed]} ozone,^{[citation needed]} hydrogen peroxide,^[6] singlet oxygen^{[citation needed]} and other metastable
  or unstable species which spontaneously react without further reactants
• in particular, the vast majority of
  free radicals^[7]
• explosives such as nitroglycerin
  and other substances which react exothermically without requiring a second reactant
• oxidized
  to release energy

The term is often used without a definition. Some authors define the term "high-energy" to be equivalent to "chemically unstable", while others reserve the term for high-energy phosphates, such as the Great Soviet Encyclopedia which defines the term "high-energy compounds" to refer exclusively to those.

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