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Author: Subject: Report on making Tin Iodide and Antimony Iodide
Lion850
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[*] posted on 24-11-2019 at 01:00
Report on making Tin Iodide and Antimony Iodide


After seeing videos on YouTube I wanted to make Tin Iodide SnI4. It turned out to be reasonably straightforward. I made 2 batches.
First:
- 200ml of dichloromethane
- 8g Iodine
- 6g Tin granules
Contents placed in a 500ml beaker. A 500ml RBF filled with water was placed on top of the beaker (RBF supported by a stand) to act as a simple reflux. The DCM was brought to a gentle boil with magnetic stirring. After 45 minutes not much happened, I then lifted the RBF to let the DCM escape and thus reduce the overall volume. Once the volume was under 100ml the color started clearing, by the time it was down to around 70ml it was a nice orange with no more sign of Iodine. I filtered it off into a small beaker and boiled it down to 20ml, at which point there was already a substantial amount of orange precipitate. I cooled the beaker in an ice bath, and filtered again. I then dried the red SnI4 crystals with paper towel and by simply leaving it out in the (hot) shed. The first run gave 8g of product.
Second:
There was still a lot of unreacted Tin granules so I added another 8g Iodine, and this time only 100ml DCM. The solution was allowed to boil down slowly and by the time it reached approximately 60ml, about 40 minutes later, the reaction was complete and the SnI4 was concentrated and recovered as above. This time the yield was 8.6g, but I am not 100% sure it was completely dry, may be a gram or so of DCM.

On YouTube I saw PoorMans Chemist' video where he made beautiful red Antimony Iodide using Toluene as solvent. I decided to try using DCM:
- 8g Iodine
- 5g Antimony powder
- 100ml DCM
After 2 hours of boiling nothing appeared to have happened. Solution stayed dark. PoorMans Chemist in fact told me that DCM may not work as Antimony needed a higher temperature, and that if it did not work to try Toluene or Xylene. So I then chucked out the reagents. But, I did see some traces of red when pouring it out....
I then went to the local hardware and got Xylene (Toluene was not immediately available near me). I started again with 7g Iodine, 4.5g Antimony powder, and 100ml Xylene. I boiled this for 2 hours (bp should be around 110 deg as per Xylene spec) but the solution stayed pitch black. I then again removed the "refluxing" RBF and allowed it to boil vigorously (always with stirring) down to around 60ml. Still pitch black. I was just about to give up and chuck the contents when I noticed 2 things: There was red spots on the sides of the beaker and then fast stirring splashed the contents up the liquid was only black with no more purple like earlier. I then wondered whether the very fine Antimony powder which was purposely in excess was staying in suspension and making the solution look black? I did a filtration of the boiling liquid (by now reduced to under 50ml) and was rewarded with a blood red filtrate with red crystals of SbI3 settling as it started to cool! I cooled it in an ice bath, filtered off the crystals, and dried on the filter paper on a slightly hot hotplate. The result was 4.6g of very beautiful red crystals with what appears to be golden specks. In fact it reminded me of the lead iodide golden rain. The photo does not really do it justice.
Next to try to make lead iodide and manganese iodide this way. I'm going to try to attached some photos, hope it works.


Beautiful SbI3.jpg - 455kB Antimony powder kept solution black.jpg - 550kB SnI4 product.jpg - 460kB Tin Iodide reaction completed.jpg - 554kB
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Lion850
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[*] posted on 24-11-2019 at 02:16


Hi guys when I view my photos in my above post on my laptop they are lying on their sides....how to turn them the correct way?

Thanks, Leo.
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[*] posted on 24-11-2019 at 03:52


This is pretty cool, Lion850. It does not sound like an overly challenging synthesis but a dramatic result.
Thanks for sharing. (And don't worry about the pictures.)
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AJKOER
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[*] posted on 3-12-2019 at 07:16


Nice experiment!
-----------------------------

FYI, comments from atomistry.com on SnI2 (at http://tin.atomistry.com/stannous_iodide.html which is constructed from extracts from old chemistry journals):

"Stannous Iodide, SnI2, is obtained by adding potassium iodide in slight excess to a concentrated solution of stannous chloride, or by the action of hydriodic acid on tin; it crystallises in orange-red octahedra, which may be obtained by melting the compound, or evaporating its solution in carbon disulphide; but it is probably dimorphous. It melts at 320° C., and boils at 720° C. The dihydrate SnI2.2H2O is said to exist; 100 parts of water dissolve 0.93 parts of anhydrous stannous iodide at 20° C., and 4.03 parts at 100° C. It is much more soluble in hydriodic acid and alkali halide solutions, owing to the formation of a complex acid or salts."


[Edited on 3-12-2019 by AJKOER]
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woelen
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[*] posted on 3-12-2019 at 11:24


Very nice synthesis of SbI3 and SnI4. I made SnI4 a few years ago:

https://woelen.homescience.net/science/chem/exps/SnI4/index....

Recently I made a somewhat larger batch of SnI4 and made a display sample of the material in a sealed glass ampoule.

----------------------------------------------------------------------------------------------

I also did an experiment with SnI2. The latter can be made in aqueous solution, although I think that isolation of the pure compound will be much harder than the isolation of SnI4.

https://woelen.homescience.net/science/chem/exps/tin+iodide/...







The art of wondering makes life worth living...
Want to wonder? Look at https://woelen.homescience.net
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Lion850
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[*] posted on 3-12-2019 at 16:20


Hi Woelen I will have a go at SnI2 when I have the time.
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Lion850
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[*] posted on 17-9-2020 at 23:18


Some 9 months since I made the Tin (iv) iodide SnI4, and after watching PoorMans Chemist's recent video where he makes tin (ii) iodide SnI2 by double displacement in water I thought it would be nice to have both iodides so also had a go. The link to PoorMans Chemist's video:
https://www.youtube.com/watch?v=fR1pem_ytYE&t=846s

I thought this would be as straightforward as they come but there were a few surprises. Expected double displacement reaction:

SnCl2.2H2O + 2KI = SnI2 + 2KCl + 2H2O.

- 7g tin chloride added to a small beaker with 30ml water & stir
- Solution stays cloudy, but if filtered the filtrate is clear and there is a white remainder.
- Add 10 drops concentrated HCl, still cloudy.

At this point I stopped to read up more...and found out that SnCl2 must always be dissolved in a small amount of water - in excess water it hydrolyses into an insoluble salt. Duh....start again.

- 7g tin chloride in 5.5g water and stir....almost clear solution!
- Dissolve 13.5g KI in 12g water, clear solution.
- Add the KI solution to the SnCl2 solution while stirring
- Yellow thick emulsion, stir bar stuck! Some orange spots forming.
- Add water slowly while stirring with a glass rod until the solution thinned enough to be moved with the stir bar.
- Mainly orange with some yellow lumps. Heat to about 50C while stirring, now mainly orange with some yellow on the edge and smooth. See photo below.
1.jpg - 777kB

- Gravity filter. Orange remainder but more yellow on top, pale yellow filtrate.
- Wash the remainder with water in the funnel and transfer to steam bath to dry. Photo below.
2.jpg - 486kB

- Color darkens a bit when hot (dry) but more orange when cool. 4g dry mainly orange powder, which was a poor yield.

Usually I clear up before leaving the shed for the night but I was called into the house and left the cleaning for the next day. Which was lucky, because the next day I saw that red crystals settled out of the beaker that has the yellow remainder. See photo below.
3.jpg - 471kB

Some of the SnI2 crystals were obviously fine enough to pass through my filter paper. I decanted the supernatant liquid, rinsed the crystals with water and decanted again, and then added this crop to the crystals drying on the steam bath. This second crop added a gram or so to the eventual dry weight, and became more orange as they dried. Photo below of the wet crystals that crystalized out overnight.
4.JPG - 313kB

After drying on the steam bath, the color of the cool dry product was a lighter orange. The photo below shows the final color on the left. The right bottle is the SnI4 made 9 months ago and stored in this clear bottle; it has held up quite well but has darkened a bit.
5.jpg - 583kB

When PoorManChemist did his reaction he also briefly got a yellow solution. I think the SnI2 appears yellow when in dilute suspension or when the solid is very fine. Once it clumps together it is more orange, and if wet red - but this is just my guess.

If I were to do this again I would make the KI solution a bit more diliute and see what happens if the SnCl2 is added to the KI instead of the other way around. My reaction probably had too little water once mixed and thus I initially ended up with the thick yellow emulsion. Again, I am just guessing.

The purity and appearance of the final product could probably be improved if it was dissolved and recrystallized, and then dried slowly at lower temperature instead of on the steam bath.


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