Is phosphorine (C₅H₅P) aromatic? Phophorine seems aromatic as it has 6 conjugated electrons. But the answer given is that it is not. This seems odd since pyridine has a similar structure and is also aromatic. Thus I ask is phospohrine aromatic or not?
Phosphorine (IUPAC: phosphinine) actually has aromatic character nearly as great (88%) as that of benzene.  According to the reference, phosphorine is sufficiently stable to be handled without air-free techniques; and it undergoes electrophilic substitution reactions similar to those of benzene.