A polyatomic ion can form an ionic bond with another ion, and an ionic bond is a type of chemical bond. Some examples:
One mole of ammonium ions plus one mole of chloride ions produces one mole of ammonium chloride.
NH4+ + Cl- ---> NH4Cl
One mole of magnesium ions plus two moles of nitrate ions produces one mole of magnesium nitrate.
Mg2+ + 2NO3- ---> Mg(NO3)2
Ions are capable of creating ionic bonds, either they exist in different atoms or cluster of atoms.
A polyatomic ion. For example, ammonium, chemical formula (NH4) with a 1+ electrical overall charge.
More than one polyatomic ion should be indicated in a chemical formula by putting parentheses around the atoms in the ions and then adding a subscript.
A polyatomic ion is held together by covalent bonds between atoms. They can be either positive or negative. For example, the ammonium ion, NH4+, has a positive charge, and the sulfate ion, SO42-, has a negative charge.
The polyatomic ion represented by the formula NO2- is the nitrite ion.
In principle, only by comparing the chemical formula for the compound with the formulas of ions known to be polyatomic to determine whether the sequence of letters and subscript numbers (if any) in any part of the chemical formula corresponds to the sequence of letters and subscript numbers in the formula of a know polyatomic ion.
Chemical bond
The atoms in a polyatomic ion are held together with covalent bonds, but polyatomic ions combine with ions of opposite charge to form ionic compounds.
A polyatomic ion is charged and will form ionic bonds; for example, the sulfate ion SO42- forms many compounds, such as sodium sulfate. The bonds holding polyatomic ions together are covalent.
An oxyanion is in the form of AxOy, where A is a chemical or polyatomic ion, and O is an oxygen.
HCO3- is the polyatomic ion with which sodium bonds. It is the bicarbonate ion.
A polyatomic ion. For example, ammonium, chemical formula (NH4) with a 1+ electrical overall charge.
A polyatomic ion.
The internal bonds within the polyatomic ion whose formula is CO3-2 are polar covalent bonds between carbon and oxygen.
Ammonium ion is polar due to the ionic bonds present in the polyatomic ion.
The chemical formula of ammonium is (NH4)+.
Atoms can covalently bond together to produce a polyatomic ion, which can form a salt with another ion of opposite charge. Carbonate, phosphate, sulfate, nitrate, acetate, and other alkanoate salts all illustrate this phenomenon.
"The atoms in polyatomic ions such as hydroxide ion, ammonium ion and sulfate ion, are held together by covalent bonds" Link: http://www.cartage.org.lb/en/themes/sciences/chemistry/inorganicchemistry/Informationbonding/CovalentBond/CovalentBond.htm