Oxygen-17 (¹⁷O) is a low-abundance, natural,

stable A stable is a building in which livestock, especially horses, are kept. It most commonly means a building that is divided into separate stalls for individual animals and livestock. There are many different types of stables in use today; the ...

isotope of oxygen (0.0373% in seawater; approximately twice as abundant as

deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two Stable isotope ratio, stable isotopes of hydrogen (the other being Hydrogen atom, protium, or hydrogen-1). The atomic nucleus, nucleus of a deuterium ato ...

). As the only stable isotope of oxygen possessing a

nuclear spin In atomic physics, the spin quantum number is a quantum number (designated ) which describes the intrinsic angular momentum (or spin angular momentum, or simply spin) of an electron or other particle. The phrase was originally used to describe th ...

(+5/2) and a favorable characteristic of field-independent relaxation in liquid water, ¹⁷O enables NMR studies of oxidative

metabolic pathways In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reac ...

through compounds containing ¹⁷O (i.e. metabolically produced H₂¹⁷O water by

oxidative phosphorylation Oxidative phosphorylation (UK , US ) or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy in order to produce adenosine tri ...

mitochondria A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...

) at high magnetic fields. Water used as

nuclear reactor coolant A nuclear reactor coolant is a coolant in a nuclear reactor used to remove heat from the nuclear reactor core and transfer it to electrical generators and the Environment (systems), environment. Frequently, a chain of two coolant loops are used b ...

is subjected to intense

neutron flux The neutron flux, φ, is a scalar quantity used in nuclear physics and nuclear reactor physics. It is the total length travelled by all free neutrons per unit time and volume. Equivalently, it can be defined as the number of neutrons travelling ...

. Natural water starts out with 373 ppm of ¹⁷O; heavy water starts out incidentally enriched to about 550 ppm of oxygen-17. The neutron flux slowly converts ¹⁶O in the cooling water to ¹⁷O by

neutron capture Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus. Since neutrons have no electric charge, they can enter a nucleus more easily than positively charged protons, ...

, increasing its concentration. The neutron flux slowly converts ¹⁷O (with much greater

cross section Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture & engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **Abs ...

) in the cooling water to

carbon-14 Carbon-14, C-14, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and coll ...

, an undesirable product that can escape to the environment: : ¹⁷O (n,α) → ¹⁴C Some

tritium Tritium ( or , ) or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with half-life about 12 years. The nucleus of tritium (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus o ...

removal facilities make a point of replacing the oxygen of the water with natural oxygen (mostly ¹⁶O) to give the added benefit of reducing ¹⁴C production.A Compact, Low Cost, Tritium Removal Plant for Candu-6 Reactors; S.K. Sood, C. Fong, and K.M. Kalyanam; Ontario Hydro

History

The isotope was first hypothesized and subsequently imaged by

Patrick Blackett Patrick Maynard Stuart Blackett, Baron Blackett (18 November 1897 – 13 July 1974) was a British experimental physicist known for his work on cloud chambers, cosmic rays, and paleomagnetism, winning the Nobel Prize for Physics in 1948. ...

in Rutherford's lab in 1925: ' It was a product out of the first man-made transmutation of ¹⁴N and ⁴He²⁺ conducted by

Frederick Soddy Frederick Soddy FRS (2 September 1877 – 22 September 1956) was an English radiochemist who explained, with Ernest Rutherford, that radioactivity is due to the transmutation of elements, now known to involve nuclear reactions. He also prove ...

and

Ernest Rutherford Ernest Rutherford, 1st Baron Rutherford of Nelson, (30 August 1871 – 19 October 1937) was a New Zealand physicist who came to be known as the father of nuclear physics. ''Encyclopædia Britannica'' considers him to be the greatest ...

in 1917–1919. Its natural abundance in Earth's atmosphere was later detected in 1929 by Giauque and Johnson in absorption spectra.

References

{{Isotope, element=oxygen , lighter=

oxygen-16 Oxygen-16 (16O) is a stable isotope of oxygen, having 8 neutrons and 8 protons in its nucleus. It has a mass of . Oxygen-16 is the most abundant isotope of oxygen and accounts for 99.762% of oxygen's natural abundance. The relative and absolute ...

, heavier=

oxygen-18 Oxygen-18 (, Ω) is a natural, stable isotope of oxygen and one of the environmental isotopes. is an important precursor for the production of fluorodeoxyglucose (FDG) used in positron emission tomography (PET). Generally, in the radiopharmaceu ...

, before=

nitrogen-17 Natural nitrogen (7N) consists of two stable isotopes: the vast majority (99.6%) of naturally occurring nitrogen is nitrogen-14, with the remainder being nitrogen-15. Fourteen radioisotopes are also known, with atomic masses ranging from 10 to 25, ...

fluorine-17 Fluorine (9F) has 18 known isotopes ranging from to (with the exception of ) and two isomers ( and ). Only fluorine-19 is stable and naturally occurring in more than trace quantities; therefore, fluorine is a monoisotopic and mononuclidic elem ...

, after=stable Environmental isotopes Isotopes of oxygen