If I only have the name of this transitional coordination compound, bis(enthylenediamine)dinitroiron (III) sulphate how do you find the 2 outside the square bracket of this same thing but in formula form? [Fe (en)2 (NO2)2]2SO4 thanks.

maybe this would help?

http://www.coursehero.com/file/p6s4k6su/Bis-ethylenediamine-More-Nomenclature-Feen-2-NO-2-2-2-SO-4-Bisethylenediamine/

To determine the formula of the transitional coordination compound, [Fe(en)₂(NO₂)₂]₂SO₄, you can analyze each component one by one. Let's break it down step by step:

1. Start by identifying the transition metal ion in the compound. In this case, it is iron (Fe).

2. Next, identify the ligands. Ligands are molecules or ions that bind to the central metal ion. In this compound, there are two different ligands:
- Bis(enthylenediamine) - This ligand is represented by (en). Ethylenediamine (en) is a bidentate ligand, meaning it can bind to the metal ion through two of its nitrogen atoms.
- Dinitro (NO₂) - This ligand is represented by (NO₂). The ligands NO₂ can also be known as nitro groups.

3. Now, calculate the charge on the central metal ion. Since the compound is [Fe(en)₂(NO₂)₂]₂SO₄, it is specified as iron (III), which means the iron ion (Fe³⁺) has a +3 charge overall.

4. Determine the charge on the sulfate ion (SO₄²⁻). Since the compound also contains a sulfate ion, we know that it carries a -2 charge.

5. Now, you need to balance the charges. Since there are two of the [Fe(en)₂(NO₂)₂]²⁺ ions, the total positive charge is 2 × 2 = +4. The sulfate ion (SO₄²⁻) has a -2 charge. So, to balance the charges, you need two sulfate ions (SO₄²⁻).

Putting it all together, you get the formula [Fe(en)₂(NO₂)₂]₂(SO₄)₂, which represents bis(enthylenediamine)dinitroiron(III) sulphate with the charge outside the square brackets.