The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Potassium Nitrosodisulfonate(Fremy's Salt) colour changes

Does anyone know why Potassium Nitrosodisulfonate is purple in solution but a bright orange/yellow when solid. I know it has something to do with the solution being paramagnetic and the solid being diagmagnetic but i don't really see the link, i need an explanation.
Original post by digchick21
Does anyone know why Potassium Nitrosodisulfonate is purple in solution but a bright orange/yellow when solid. I know it has something to do with the solution being paramagnetic and the solid being diagmagnetic but i don't really see the link, i need an explanation.


I love how you're trying to get lab report answers via Student Room. Why didn't I think of that? I'm still struggling with this son of a bitch... BSP5...
Reply 2
Avatar for Calian
Calian
It's something to do with the differences in electronic states of the ground states of a diamagnetic and paramagnetic molecule, which causes absorption of different wavelengths in the visible spectrum so they appear to be different colours. I wouldn't stress too much about going into massive detail here, I can't recall much in lectures relating paramagnetism to colour.

But if you're really scrounging for marks I suggest you use the blue colour of paramagnetic oxygen as an example. :smile:

edit: lol sorry for the late reply now, I just remembered the monday 3pm deadline for freshers.
(edited 13 years ago)
Original post by digchick21
Does anyone know why Potassium Nitrosodisulfonate is purple in solution but a bright orange/yellow when solid. I know it has something to do with the solution being paramagnetic and the solid being diagmagnetic but i don't really see the link, i need an explanation.


The ion is paramagnetic, because it has one unpaired electron (it is effectively a free radical).

When the solid is formed it becomes diamagnetic, meaning that there are no unpaired electrons. This suggests that the ion dimerises in the solid structure to pair up the electrons.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you