The Chemistry Book

Template:Polyatomics


Polyatomic Ions are comprised of more than one atom it becoms a polyatomic ion. As the atoms start behaving as a unit, the individual polyatomics are held together by covalent bonds.[1] For example a nitrate ion contains three covalent bonds. Polyatomic ions are ions that consist of more than one atom. For example, nitrate ion, NO3-, contains one nitrogen atom the three oxygen atoms. The atoms in the polyatomic ion are usually covalently bonded to one another, and therefore stay a single charged unit.[2]


A polyatomic ion is a charged species (ion) composed of two or more atoms covalently bonded that can be considered as acting as a single unit.

Common polyatomic ions should be memorized. Image is from Sartep

[3].The atoms within a polyatomic ion are usually very tightly bonded together, so the ion remains it's identity within ion compounds and over the course of many chemical reactions. charged species ions are composed of two or more atoms covalently bonded of or metal complex that can be considered as acting as a single unit in context of acid and base chemistry or in formation of salts.

The prefix of poly means many words in Greek, but even ions of two atoms are commonly referred to as polyatomic.CITATION REQUIRED

Note: a polyatomic ion is also referred to in older works as a radical.CITATION REQUIRED

Contents

Rules

To get -ite, subtract 1 from an -ate Ex. Sulfate=SO4-2, sulfite= SO3-2 To add hydrogen, increase the charge by 1 Ex. Sulfate=SO4-2, Hydrogen Sulfate+ SO4-1[4] (needs to be Verified) Rlue1: The cation is written first in the name; the anion is written second in the name. Rule 2: When the formula contains one or more of the same polyatomic ion it is written in parenthesis with the subscript written on the outside of the parenthesis. Note: Parenthesis and a subscript are not used unless more than the same polyatomic ion are present in the formula unit (e.g. the polyatomic ion for calcium sulfate is (CaSO4) not Ca (SO4)) Rule 3: If a cation is a metal ion with a fixed charge, the name of the cation is the same as the (neutral) element from which it is derived. If the cation is a metal ion with a variable charge, the charge on the cation is indicated using a roman numeral, in parenthesis, immediately following the name of the cation.[5]


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Things to Remember
It is important to memorize these polyatomic ions. Failure to memorize these will cause pain later as you study chemical reactions, balancing equations, and stoichiometry.

Charts

Cation Name
NH4+ Ammonium
Hg22+ Mercury (I)
Anion Name
NO2- Nitrite
NO3- Nitrate
SO32- Sulfite
SO42- Sulfate
HSO4- Hydrogen sulfate
OH- Hydroxide
CN- Cyanide
PO43- Phosphate
HPO42- Hydrogen phosphate
H2PO4- Dihydrogen phosphate
NCS- Thiocyanate
CO32- Carbonate
HCO3- Hydrogen carbonate
ClO- Hypochlorite
ClO2- Chlorite
ClO3- Chlorate
ClO4- Perchlorate
C2H3O2- Acetate
MnO4- Permanganate
Cr2O72- Dichromate
CrO42- Chromate
O22- Peroxide
C2O42- Oxalate


Further Reading

References

  1. ↑ http://www.chem.purdue.edu/gchelp/nomenclature/poly_atom.htm
  2. ↑ https://www.amazines.com/Polyatomic_ion_related.html
  3. ↑ http://www.chem.purdue.edu/gchelp/nomenclature/poly_atom.htm
  4. ↑ http://home.earthlink.net/~ssbeaton/addlinfo/polyions.html
  5. ↑ "ionic compounds containing polytomic ions" retrieved February 6 2009 http://www.chem.purdue.edu/gchelp/nomenclature/poly_atom.htm

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