Question

What is the name of the ionic compound - $\text{N}{{\text{a}}_{\text{3}}}\text{Al}{{\text{F}}_{\text{6}}}$?

Answer 1

Nomenclature of an ionic compound is very simple and it involves identification of cation and anion in the compound and then the name can be obtained by writing the cation name followed by the anion name. $\text{N}{{\text{a}}_{\text{3}}}\text{Al}{{\text{F}}_{\text{6}}}$ is an ionic compound that is made up of sodium cation and a complex anion.

Complete answer:
An ion is an atom or molecule with an electrical charge. Ions having negative charges are called anions and are formed when an atom or molecule gains electrons. Usually, non-metals form negatively charged ions. Ions that carry positive charge are called cations and are formed when an atom or molecule loses electrons from its outermost orbital. All metals form cations.
These oppositely charged cations and anions form ionic bonds due to the electrostatic attraction between the ions and this results in the formation of the ionic compounds.
The nomenclature of ionic compounds is very simple. The names are given by writing the name of cation first, followed by the name of a negatively charged anion.
If the metal cation can have more than one oxidation state then the roman numeral is used to write the oxidation number of cations enclosed inside a parenthesis.
So, let us write the name of the given ionic compound - $\text{N}{{\text{a}}_{\text{3}}}\text{Al}{{\text{F}}_{\text{6}}}$:
1 – First, we need to identify the cation and the anion in the compound. In this case, the cation is the sodium ion and the anion is $\text{AlF}_{_{\text{6}}}^{3-}$ which is a complex ion.
2 – The suffix -ate will be used with the name of ion as it is a polyatomic ion. Since it is a complex ion, the ligand’s name will end with -ido and the oxidation number of the central atom (Al) should be written in parenthesis. So, we have:
Name of cation – Sodium ion
Name of anion – Hexafluoridoaluminate (III) ion
3 – Now, simply join the name of ions with the name of the cation followed by the name of the anion.
Hence, the name of the ionic compound - $\text{N}{{\text{a}}_{\text{3}}}\text{Al}{{\text{F}}_{\text{6}}}$ is Sodium hexafluoridoaluminate (III).

Additional information: $\text{N}{{\text{a}}_{\text{3}}}\text{Al}{{\text{F}}_{\text{6}}}$ is a white solid, occurs naturally as the mineral cryolite, and is used in the industrial production of aluminium metal.

Note:
In an ionic compound, if the anion is a monatomic ion, then the suffix -ide is used with its name. For example: chloride ion $\left( \text{C}{{\text{l}}^{-}} \right)$. And when the anion is a polyatomic ion, the suffix -ate is used. For example: sulphate ion $\left( \text{SO}_{4}^{-} \right)$.