Question

The correct name of the compound $[Cu{(N{H_3})_4}]{(N{O_3})_2}$ according to IUPAC system is:
A. Cuprammonium nitrate
B. tetrammine copper(II) dinitrate
C. tetrammine copper(II) nitrate
D. tetrammine copper(III) dinitrate

Answer 1

As we can see in the question the name of the ligand needs to be written as per the IUPAC rules, so here we need to know the IUPAC rules and on calculating the oxidation state and by knowing the charge of the ligand we can easily name the complex coordinate compound.

Complete answer
Rules are as follows:
1. First name the cation than the anion.
2. Write the name of the ligand first than the metal ion.
3. Ligand name ends with “o” if it is negative and remains the same if it is neutral with no charge.
4. Numbers are defined in the Greek language, Greek prefix (mono, di, tri, tetra, penta, hexa, etc.) if ligands contain such prefix than the alternate. The prefix is used known as bis, tris, tetra.
5. Oxidation number of the metal is written in roman numbers.
6. If complexes have negative charge the ferrate, cuprate, nickelate, cobaltate etc. is used instead of ferric, cupric etc.
7. For more than one ligand the alphabetical order is followed to write the name of the complex.
Let’s apply the rule to write the formula.
We have to calculate the oxidation state of copper first it can be calculate if the charge of the ligand is known the charge of $N{H_3}$ is neutral and the charge of $N{O_3}$ is $- 1$.

$$[Cu{(N{H_3})_4}]{(N{O_3})_2}\\\ x + 4(0) + 2( - 1) = 0\\\ x = + 2$$

Hence the value of oxidation no. of $Cu$ will be $+ 2$.

Hence, the name of the complex is (B) tetraamine copper(II) dinitrate.

Because as per the rule first write the name of the ligand as per the alphabetical order then write the name of the metal and its oxidation number and then the ligand which is ambivalent.

Note:
These rules are fixed for the complexes for complex coordinate compounds. IUPAC stands for international union of pure and applied chemistry. It forms the rules or changes the rule and it is valid and followed by all the countries.