Subject: why is vanadium (v) oxide coloured?

   I remember in chemistry class being taught that transition elements 
( f blocks elements) exhibit coloured compounds / ions due to having 
unpaired d electrons ( i don't want to bore you any more details). I 
was reading this chemistry magazine when i came across Vanadium (V) 
Oxide, which is yellow-orange in colour. What kind of confused me is 
that , despite of the fact that the vanadium ion in Vanadium pentoxide 
( vanadium having an oxidation state of +5)has no unpaired d electrons 
( electronic config. of d orbital being 0) it still forms a coloured 
compound...why is that?  

Thank you .

Re: why is vanadium (v) oxide coloured?