Sciencemadness Discussion Board

Indium compounds

Wizzard - 12-5-2011 at 05:39

Just playing around with my elements again, I figured I'd try making some nice crystals of Indium salts...

Dropping In into medium sulfuric acid (35% I think) produced a transparent liquid- As expected. Still awaiting crystals :)

Depositing In into white fuming HNO3 made at first a light-yellow solution, which became orangy (NO3) and then a wonderful emerald green- Like Ni sulfate.

I thought Indium(III) nitrate was white? Did I make something else? I have no idea what color In(II) or In(I) is, not much information out there. Or do I just have a very impure sample?

Jor - 12-5-2011 at 06:53

Can you dilute the indium nitrate solution. I think it will turn clear. or boil it.
When you dissolve copper the green color is also observed, it seems NO2 dissolved in conc. nitric acid forms some sort of green complex with copper and other metals. When you dilute it the color goes blue (in the case of copper).

[Edited on 12-5-2011 by Jor]

ScienceSquirrel - 12-5-2011 at 07:15

A few minutes searching would have revealed the fact that getting crystals of indium nitrate or suphate is likely to be quite hard.
The salts are very soluble in water, hygroscopic and decompose on heating.
They are also boring white solids.
I think the colour must be due to contamination, indium III would be the species formed under those conditions and it is white. Indium I is a powerful reducing agent.


http://en.wikipedia.org/wiki/Indium%28III%29_sulfate


http://www.indium.com/_dynamo/download.php?docid=150

Wizzard - 12-5-2011 at 07:46

Yeah, I like the shapes :) And I was going to dry them out very slowly with a low vacuum (almost 14") at room temperature, see if I could get any crystals. The indium sulfate has not lost any water yet, I see :p

I will dilute the nitrate solution, and see what happens. Thanks for the suggestion :)

ScienceSquirrel - 12-5-2011 at 08:40

That might work.
I doubt the colour is due to an indium complex.
I would expect the chemistry to be similar to aluminium and most of it's compounds are white except where the anion is coloured.

Wizzard - 12-5-2011 at 09:55

Ah, what fun... With the addition of another 1.2cc of water, all the color is gone :( How plain.

Time to dehydrate!

Would anybody care to link me to something I can read about the wonderfully colorful complex which was formed?