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An electrostatic potential map of the nitrate ion (NO−3). Areas coloured translucent red, around the outside of the red oxygen atoms themselves, signify the regions of most negative electrostatic potential.
A polyatomic ion (also known as a molecular ion) is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zero.[1] The term molecule may or may not be used to refer to a polyatomic ion, depending on the definition used. The prefix poly- carries the meaning "many" in Greek, but even ions of two atoms are commonly described as polyatomic.[2]
In older literature, a polyatomic ion may instead be referred to as a radical (or less commonly, as a radical group). In contemporary usage, the term radical refers to various free radicals, which are species that have an unpaired electron and need not be charged.[citation needed][3]
A simple example of a polyatomic ion is the hydroxide ion, which consists of one oxygen atom and one hydrogen atom, jointly carrying a net charge of −1; its chemical formula is OH−. In contrast, an ammonium ion consists of one nitrogen atom and four hydrogen atoms, with a charge of +1; its chemical formula is NH+4.
Polyatomic ions often are useful in the context of acid–base chemistry and in the formation of salts.
Often, a polyatomic ion can be considered as the conjugate acid or base of a neutral molecule. For example, the conjugate base of sulfuric acid (H2SO4) is the polyatomic hydrogen sulfate anion (HSO−4). The removal of another hydrogen ion produces the sulfate anion (SO2−4).
^Petrucci, Ralph H.; Herring, F. Geoffrey; Madura, Jeffry D.; Bissonnette, Carey (2017). General chemistry: principles and modern applications (Eleventh ed.). Toronto: Pearson. p. A50. ISBN 978-0-13-293128-1.
A polyatomicion (also known as a molecular ion) is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave...
element, it is called a polyatomicion. For example, calcium carbonate consists of the monatomic cation Ca2+ and the polyatomic anion CO2− 3; both pentazenium...
compounds. Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomicions. In the...
Nitrate is a polyatomicion with the chemical formula NO− 3. Salts containing this ion are called nitrates. Nitrates are common components of fertilizers...
carbonic acid, H2CO3, characterized by the presence of the carbonate ion, a polyatomicion with the formula CO2−3. The word "carbonate" may also refer to a...
The ammonium cation is a positively charged polyatomicion with the chemical formula NH+4 or [NH4]+. It is formed by the protonation of ammonia (NH3)....
nomenclature discrepancies exist. This linkage is recognized as a common polyatomicion, and exists in many molecules. The characteristic structure of a peroxide...
In organic chemistry, an iminium cation is a polyatomicion with the general structure [R1R2C=NR3R4]+. They are common in synthetic chemistry and biology...
captured by the electron cloud of an atom. The result is a diatomic or polyatomicion containing hydrogen. In a vacuum, when free electrons are present, a...
polyatomic ions. Therefore, the name of the metal or positive polyatomicion is followed by the name of the non-metal or negative polyatomicion. The positive...
from ions is dropped and molecule is often used when referring to polyatomicions. A molecule may be homonuclear, that is, it consists of atoms of one...
These polyatomicions are groups of atoms that are covalently bound together and have an overall ionic charge, such as the sulfate [SO4]2− ion. Each polyatomic...
somewhat differently for molecules than for crystals. For molecules and polyatomicions the coordination number of an atom is determined by simply counting...
carboxylate salts (−COO−), which turns the molecule into a polyatomicion or a complex ion. Functional groups binding to a central atom in a coordination...
Some bacteria can metabolise thiosulfates. Thiosulfate ion is produced by the reaction of sulfite ion with elemental sulfur, and by incomplete oxidation of...
explaining the metallic conduction. The polyatomicion C4−3, sometimes called allylide, is found in Li4C3 and Mg2C3. The ion is linear and is isoelectronic with...
The nitronium ion, [NO2]+, is a cation. It is an onium ion because its nitrogen atom has +1 charge, similar to ammonium ion [NH4]+. It is created by the...
positively-charged polyatomicions of the structure [NR4]+, where R is an alkyl group, an aryl group or organyl group. Unlike the ammonium ion (NH+4) and the...
strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible. potassium chromate potassium dichromate Chromates...
temperatures it isomerizes to formic acid. The double ionized ion, CO2−2, is known as the carbonite ion. Schreiner, Peter R.; Reisenauer, Hans Peter (2008). "Spectroscopic...
isomerization or isomerisation is the process in which a molecule, polyatomicion or molecular fragment is transformed into an isomer with a different...
The arsonium cation is a positively charged polyatomicion with the chemical formula AsH+ 4. An arsonium salt is a salt containing either the arsonium...
ionize the sample. It atomizes the sample and creates atomic and small polyatomicions, which are then detected. It is known and used for its ability to detect...
The sulfate or sulphate ion is a polyatomic anion with the empirical formula SO2−4. Salts, acid derivatives, and peroxides of sulfate are widely used...
In chemistry, a polyoxometalate (abbreviated POM) is a polyatomicion, usually an anion, that consists of three or more transition metal oxyanions linked...
The corresponding triflate anion, CF3SO−3, is an extremely stable polyatomicion; this comes from the fact that triflic acid (CF3SO3H) is a superacid;...
units, unlike ions. When this rule is broken, giving the "molecule" a charge, the result is sometimes named a molecular ion or a polyatomicion. However,...
of minerals with Wikipedia articles List of alchemical substances Polyatomicion – Ion containing two or more atoms Exotic molecules – Atoms composed of...
or protonated molecular hydrogen (IUPAC name: hydrogenonium ion) is a cation (positive ion) with formula H+3, consisting of three hydrogen nuclei (protons)...
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