Formula H[2H] | Molar mass 3.02204 g/mol | |
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Related hydrogens | ||
Hydrogen deuteride is a diatomic molecule substance or compound of the two isotopes of hydrogen: the majority isotope 1H protium and 2H deuterium. Its proper molecular formula is H2H but for simplification it is usually written as HD.
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Natural abundance
Hydrogen deuteride is a minor component of naturally occurring molecular hydrogen. In particular, hydrogen deuteride is one of the minor but noticeable components of the atmospheres of all the giant planets, with abundances from about 30 ppm to about 200 ppm. HD has also been found in supernova remnants, and other sources.
Radio emission spectra
HD and H2 have very similar emission spectra, but the emission frequencies differ.
The frequency of the astronomically important J = 1-0 rotational transition of HD at 2.7 THz has been measured with tunable FIR radiation with an accuracy of 150 kHz.