Source: cirosantilli/why-phosphorus-has-multiple-valencies
= Why phosphorus has multiple valencies?
https://www.quora.com/Why-does-phosphorous-have-a-valency-of-3-and-5
= Why phosphorus has multiple valencies?
https://www.quora.com/Why-does-phosphorous-have-a-valency-of-3-and-5