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monoanion

A monoanion is an ion carrying a single negative charge, designated with a -1 charge. This distinguishes it from dianions, which carry a -2 charge, and other polyatomic anions with higher charges. Monoanions can be inorganic or organic and are common in chemistry and biochemistry.

Common examples of monoanions include chloride (Cl−), hydroxide (OH−), nitrate (NO3−), nitrite (NO2−), acetate (CH3COO−), formate

In solution, monoanions behave as electrolytes and participate in a range of reactions depending on their identity.

The term monoanion emphasizes the negative one charge rather than specific structure or composition. Monoanions form

See also: anion, polyatomic ion, dianion.

(HCOO−),
cyanide
(CN−),
and
bicarbonate
(HCO3−).
Many
monoanions
are
the
conjugate
bases
of
their
corresponding
acids;
for
instance,
Cl−
is
the
conjugate
base
of
hydrochloric
acid
(HCl)
and
NO3−
is
the
conjugate
base
of
nitric
acid
(HNO3).
Not
all
monoanions
arise
from
simple
deprotonation,
but
the
charge
state
is
the
defining
feature.
Some
act
as
bases
(for
example,
hydroxide),
others
as
nucleophiles
(such
as
cyanide
or
acetate
under
certain
conditions),
and
some
are
comparatively
weak
bases
(such
as
nitrate).
The
acidity
of
the
parent
acid
generally
influences
the
basicity
of
the
monoanion:
conjugate
bases
of
strong
acids
tend
to
be
weak
bases.
salts
and
participate
in
acid–base
chemistry,
redox
processes,
and
various
industrial
and
biological
reactions.