I want to know why the formula of mercurous chloride is Hg 2 Cl 2 and why can't it be written as HgCl (simple ratio) ?

I want to know why  the formula of mercurous  chloride is Hg2Cl2 and why can't it be written as HgCl (simple ratio) ?


3 Answers

Ashwin Sinha
520 Points
12 years ago


 Mercury (I) chloride also known as Mercurous chloride or calomel has been used for centuries and is a well known compound.

Crystallographic studies on the compound show that in the crystalline form it has the following structure:


The is a Hg-Hg bond, making the compound a dimer, hence the Hg2Cl2 formula.




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Ritvik Gautam
85 Points
12 years ago

This is because in the natural state is formed as Hg2Cl2. There is some intermolecular forces which keep the two molecules together. This is similar to the case of Aluminium Chloride. In nature it is found as Al2Cl6. But in theory it is also written as AlCl3. So, as far as theory is concerned it doesn't really matter how you write but it is prefered to write as Hg2Cl2.



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Sanjeev Malik IIT BHU
101 Points
12 years ago

this is a quite different case.

here there is metallic bonding between two Hg atoms.

it is bonded as   ( Hg+--Hg+). thus on whole used as  ne single molecule  Hg22+


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