Question
PCl5 exists as [PCl6]– [PCl4]+ but PBr5 exists as [PBr4] + [Br]–. Explain.
Solution
Both PCl5 and PBr5 have trigonal bipyramidal geometry. This is not a regular structure and is not very stable. Therefore, PCl5 splits up into more stable octahedral and tetrahedral structures. Which are stable than trigonal bipyramidal.
On the other hand, PBr5 splits up into stable tetrahedral structure as [PBr4]+ [Br]–
This splitting is different from PCl5 because Br atoms are large and six atoms of Br cannot be easily accommodated around smaller P atom.
On the other hand, PBr5 splits up into stable tetrahedral structure as [PBr4]+ [Br]–
This splitting is different from PCl5 because Br atoms are large and six atoms of Br cannot be easily accommodated around smaller P atom.
