Sciencemadness Discussion Board

What can I do with caesium chloride?

Twospoons - 2-3-2009 at 18:07

I have an opportunity to pick up some caesium chloride. Before I do I'd like to know if there is anything interesting I can use it for, otherwise I'll let someone else take it.

Converting to caesium metal appeals, but would probably be fairly tricky I assume, given its reactivity.

Suggestions?

chemoleo - 2-3-2009 at 18:17

If you look into the big seminal thread 'sodium by chemical methods' (or whatever it is called again), there's an attachment of someone (SC WACK i.r.c) that describes the Cs production from CsOH, using Mg filings, in suspension of a paraffin. I remember trying this with NaOH and candle wax but it didn't work. Possibly because Na-stearate was produced (this was years ago, I've learned since).
Anyway, on paper this seemed a very feasible method of producing Cs metal (as well as other alkalis). I have CsCl too, with the intent of trying exactly this...one day :)

Paddywhacker - 2-3-2009 at 20:41

Make caesium carbonate. Google "cesium effect" for its use in organic synthesis.

pantone159 - 3-3-2009 at 00:36

Does it give interesting/strong colors in flame tests?

sparkgap - 3-3-2009 at 01:29

@pantone:I'm getting conflicting accounts, with some saying it's not that different from potassium, others saying it burns blue (hence the name "caesium").

sparky (~_~)

Jor - 3-3-2009 at 01:45

Caesium salts are fairly interesting in exotic inorganic synthesis.
Many complex-ions are not stable as the K- or Na-compound, but they are as the Rb- or Cs-compound because these ions are soo large.

For example CsBr3. Not Cs in 3+ oxidation state, but it is actually a Br3(-) anion, just like I3(-).

Woelen has some examples (polyhalides):

http://homechemistry.org/index.php?title=Preparation_of_rubidium_tetrachloro_iodate_(III) (bet this works with Cs as well)

http://81.207.88.128/science/chem/compounds/cesium_dichlorobromide.html
http://81.207.88.128/science/chem/compounds/cesium_tribromide.html

I think this stabilising property is the most interesting part of cesium-chemistry.

DJF90 - 3-3-2009 at 04:23

I'm sure if you look closely in Brauer you will find that KI3 can be prepared also (IIRC). I'm unsure as to whether NaI3 is listed or not :(

sparkgap - 3-3-2009 at 04:40

Not only that, caesium triiodide has further higher homologues, e.g. CsI<sub>5</sub>, CsI<sub>7</sub> ...

sparky (~_~)

woelen - 4-3-2009 at 02:28

Cesium also is interesting for flame color experiments. I made some CsBrO3 (which is only very sparingly soluble) and mixed this with sulphur. This gives an incredible blue light when ignited. CsClO3 or CsNO3 also could be made, but these are more soluble and are less easily separated. CsClO4 also is an option, but this compound is not as easily ignited as the others.

Unfortunately, Cs-based compositions only are useful as small-scale lab curiousities. They simply are too expensive for larger-scale work.

But I would say, if you can pickup the CsCl for a decent price, I would suggest you to do so. It is interesting stuff for the somewhat more advanced home chemist.

The polyhalide compounds, mentioned by Jor, also are very interesting. These compounds are remarkably stable with Cs and Rb and they also are rather energetic oxidizers (especially the ones having a large amount of chlorine in them). If you experiment with these polyhalides, then be very careful when you mix the solid with strong reductors like metal powders or red phosphorus. Such mixes can be self-igniting, especially when slightly damp. Be careful!!!

densest - 4-3-2009 at 08:28

Aren't Cs salts (especially CsI) used to prepare density gradients in aqueous solutions for separations in cellular biology?
And for density tests in geology?

Twospoons - 4-3-2009 at 14:09

Quote:
Originally posted by woelen
But I would say, if you can pickup the CsCl for a decent price, I would suggest you to do so.


I think 'free' is a pretty good price :D

Looks like I'm getting about 300g ! - old stock being dumped from a school chem lab, stuff that was apparently donated to them in the past and they have no use for.

woelen - 4-3-2009 at 15:02

That is very good. Cs-salts are fairly expensive. I had to pay GBP 15 (appr. $25) for 100 grams of CsNO3. If you want to by new CsCl from a chemical supplier, then I think that you even have to pay more than $50 per 100 gram.

pantone159 - 4-3-2009 at 15:19

Quote:
Originally posted by woelen
If you want to by new CsCl from a chemical supplier, then I think that you even have to pay more than $50 per 100 gram.

I've noticed that CsCl is often a very high grade, overkill for a home lab probably, which presumably pushes up the price. E.g. I see one place with the cheapest price US$76 per 100g, but this is 0.99999 Cs.

chemoleo - 4-3-2009 at 16:03

The reason is, it is used in CsCl density gradient centrifugation, in biological experiments, and this requires high purity.

Ozone - 4-3-2009 at 17:46

It is also used as a matrix modifier when running graphite furnace AA. This is a very sensitive technique and high purity is a must.

Nice flame test, too.

Cheers,

O3