I've spent some hours trying to understand what exactly is a phosphoester bond, but I'm still confused and at this point I just want to throw myself out of the window. I've already read that post which treats the question but it doesn't really help me since, according to the link given by WYSIWYG♦:
A phosphoester bond is a bond between the phosphorous atom of a phosphate group and an oxygen atom.
But considering the answer of electronpusher:
Each nucleotide contains one phosphoester bond (between a phosphate O and sugar 5'-C).
It doesn't really make sense to me, since such a bond (in a nucleotide) is not exactly a bond between the phosphorous atom of the phosphate group and an oxygen atom (that is, it's a O-C bond, not a P-O bond).
So, what is exactly a phosphoester bond? Is it a O-glycosidic bond between the sugar (ribose or 2'-deoxyribose, in a nucleotide) and the phosphate group? Or is it the bond that there is between the phosphorous atom of a phosphate group and an oxygen atom of the same phosphate group?
I'm really confused and desperate by all this, so any help would be greatly appreciated. Thanks in advance!