An antiferroquadrupole is another name for an antiferromagnetic quadrupole - in which a magnet with two identical poles attracts rather than repels.

A nuclear electric quadrupole moment describes the effective shape of the ellipsoid of nuclear charge distribution. The quadrupole moment depends upon the size and charge of the nucleus.

Granit Konstantinovich Semin has written:

'Nuclear quadrupole resonance in chemistry' -- subject(s): Nuclear quadrupole resonance spectroscopy

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It is not possible to create a magnet with two south poles or two north poles. Both the poles always exist along with each other.

Force 2 magnets together end to end with the south poles together. You will get a north pole at each end and a big south pole in the middle. This arrangement is called a quadrupole.