Illustrated Glossary of Organic Chemistry
(1) The joule. An International System of Units energy unit
equal to an applied force of one newton through a distance of one
meter, or the energy equivalent to passing an electric current of
one ampere through a resistance of one ohm for one second. When
used as an energy unit, J is not italicized, for example, 16 kJ
(2) In NMR
constant. When denoting a coupling
is italicized, for example J = 7 Hz.
The distance between the lines in this doublet
is 7 Hz, so J
= 7 Hz.