Question

What would be the formula for diphosphorus pentoxide?

Answer 1

Hint: The chemical formula for diphosphorus pentoxide is ${{P}_{2}}{{O}_{5}}$ which is its empirical formula. The actual formula is ${{P}_{4}}{{O}_{10}}$ which has an adamantane (cage-like) structure. Diphosphorus pentoxide is also simply known as ‘Phosphorus pentoxide’.

Complete answer: Diphosphorus pentoxide is a white crystalline solid compound which is an anhydride of phosphoric acid. It is a powerful desiccant and dehydrating agent. The ${{P}_{4}}{{O}_{10}}$ has a cage-like structure which is reminiscent of adamantane
- Let us solve it by dividing the name into simpler components and then convert them into their respective representations as follows:-
The first name is diphosphorus which can be divided as ‘di’ and ‘phosphorus’:-
Di means ‘2’
Phosphorus is represented by ‘P’.
The first name is pentoxide which can be divided as ‘penta’ and ‘oxide’:-
 Penta means 5 (‘a’ of penta is omitted as it becomes a prefix of oxide).
 Oxide is represented by ‘O’.
-From the above explanation we may come to the conclusion that the chemical formula for diphosphorus pentoxide is ${{P}_{2}}{{O}_{5}}$. But ${{P}_{2}}{{O}_{5}}$ is an empirical formula and its actual formula is ${{P}_{4}}{{O}_{10}}$.
-${{P}_{4}}{{O}_{10}}$ has a cage-like structure which is reminiscent of adamantane. It is prepared by burning tetraphosphorus with sufficient supply of oxygen:-
${{P}_{4}}+5{{O}_{2}}\to {{P}_{4}}{{O}_{10}}$

Note: Remember that phosphorus pentoxide itself is not flammable but it reacts vigorously with water and water containing substances like cotton or wood which liberates much heat and can even cause fire hazard due to the highly exothermic nature of such reactions.