Question

Using IUPAC norms. Write the formula of ammonium tetrachlorocobaltate (II)?

Answer 1

. The full form of IUPAC is “The International Union of Pure and applied chemistry”. The IUPAC nomenclature is preferred over common name because IUPAC name of any compound is standard all over the world while common name may vary but IUPAC name is standard.

Complete step by step answer:
A complex compound is either composed of simple cation and complex anion or composed of complex cation and simple anion. Sometimes the compounds are also composed of complex cation and complex anion. Ammonium tetrachlorocobaltate (II) from the name given we can say that this complex compound is composed of simple cation and complex anion.
The cation present in the given compound is ammonium and the complex anion is tetrachlorocobaltate.

Let’s first know the IUPAC nomenclature to name the organic compounds:
1. The cation present in the compound is named first, followed by anion.
2. If it is a complex ion,
-firstly, name the ligand according to the alphabetical order.
-The greek prefixes are used to designate the number of each ligand present in the complex. Eg: tetraamine.
-The metal is named last and specifies the oxidation number of the central metal atom.
3. In case of ionic complex compounds, the complex anion which consists of a central atom and the ligand bonded to it is put inside a coordination sphere [ ].
The above mentioned points are the basic norms to name complex compounds.
Name given: ammonium tetrachlorocobaltate (II)

Complex anion: Firstly we shall follow point 2 under IUPAC norms.
-firstly, name the ligand according to the alphabetical order.
The ligand is fluoro (${F^ - }$).
-The greek prefixes are used to designate the number of each ligand present in the complex. Eg: tetraamine. So, it is $F_4^ -$.
-The metal is named at last. Hence, the central metal atom is cobalt which is represented as Co.
Thus, $[Co{F_4}]$.
The simple cation is ${(N{H_4})_2}$
Always the cation is positioned first in molecular formula too. Hence the compound is ${(N{H_4})_2}[Co{F_4}]$ ${(N{H_4})_2}[Co{F_4}]$.
Thus, the formula of ammonium tetrachlorocobaltate (II) is ${(N{H_4})_2}[Co{F_4}]$

Note: While writing the formula points to observe and remember:
-According the name given in the question, the compound has the oxidation state (II), which is nothing but the charge of cation, so it is ${(N{H_4})_2}$.