Oxygen-17
Oxygen-17 is a low abundant isotope of oxygen (0.0373% in seawater; approx. twice as abundant as Deuterium). Being the only stable isotope of oxygen possessing a nuclear spin(+5/2) and a favorable characteristic of field-independent relaxation in liquid water, this enables NMR studies of oxidative metabolic pathways through compounds containing 17O at high magnetic fields (i.e. metabolically produced H217O water by oxidative phosphorylation in mitochondria).
History
The isotope was first hypothesized and subsequently imaged by Patrick Blackett in Rutherford's lab 1924:
It was a product out of the first man-made transmutation of 14N and 4He2+ conducted by Frederick Soddy and Ernest Rutherford in 1917-1919. Finally its natural abundance in earth atmosphere was detected in 1929 by Giauque and Johnson in absorption spectra.
Characteristics
Excess mass: -809 keV
Possible parent nuclides: β from 17N, electron capture from 17F
References