Sciencemadness Discussion Board - Cheap Potassium Iodide

Cheap Potassium Iodide

JJay - 30-8-2018 at 17:09

I just ran across some cheap potassium iodide and thought people might be interested: https://www.ebay.com/itm/100g-3-52oz-Pure-Potassium-Iodide-C...

Thanks

Sulaiman - 31-8-2018 at 01:02

Even though I still have c50g I could not resist buying 100g at that price.

... stock up, be ready for the next nuclear event ..........

For similar reasons I also have excess stock of iodine prills.
... I now need to do lots of iodine based chemistry ...

JJay - 31-8-2018 at 01:54

I considered buying a kilogram but placed a small order for only 500 grams instead. Potassium iodide is expensive... 500 grams is only about 3 moles. Still, that's one of the best prices I've seen.

Ubya - 31-8-2018 at 05:03

bought 100g just for the price, at the moment i don't have to use it

highpower48 - 31-8-2018 at 07:09

Only problem I see is a 98% seller rating. I just got burned on an order of resistors. This is the first time that I was attempted to be scammed on eBay. I did recieve my money back, through eBay. But now I have to find another dealer who has 5watt resistors and reorder. The bad dealer had a rating of 99.3%.

I would love to get a couple of 100 grams of potassium iodide to make elemental iodide but this one seems just to good to be true.

CobaltChloride - 31-8-2018 at 07:21

I bought some KI from such a seller on eBay and the chemical didn't have any problems. I bought my 100g of KI from here: https://www.ebay.com/itm/100g-3-52oz-Pure-Potassium-Iodide-C...

It doesn't seem to contain any other halogens besides iodine. I combined a bit of the KI and some oxone (in excess) in a test tube, added a bit of water and I didn't get any brown or yellow-green fumes, just some black solid and a bit of purple vapor afterwards.

The only problem with this KI is that it is slightly wet and sticks to its container. This can be solved by putting the KI in a dessicator for a few days.

JJay - 31-8-2018 at 08:01

Quote: Originally posted by CobaltChloride

I bought some KI from such a seller on eBay and the chemical didn't have any problems. I bought my 100g of KI from here: https://www.ebay.com/itm/100g-3-52oz-Pure-Potassium-Iodide-C...

It doesn't seem to contain any other halogens besides iodine. I combined a bit of the KI and some oxone (in excess) in a test tube, added a bit of water and I didn't get any brown or yellow-green fumes, just some black solid and a bit of purple vapor afterwards.

The only problem with this KI is that it is slightly wet and sticks to its container. This can be solved by putting the KI in a dessicator for a few days.

Now that is a good price. I plan on testing mine when it arrives, and I will of course demand my money back if it isn't reasonably good quality.

woelen - 31-8-2018 at 10:30

Some time ago, I ordered 300 grams of this seller and I am happy with the stuff. For just over EUR 15 I have 300 grams of decent quality KI, which is a very good price.

happyfooddance - 31-8-2018 at 16:27

Shipping says estimated 6 weeks

Tdep - 31-8-2018 at 19:15

I might grab some too, good link thanks. But yeah, good thing I don't want it urgently, the shipping estimate to Aus is 7-12 weeks wow

woelen - 3-9-2018 at 00:42

Oh yes, shipping takes a loooooooong time. Just order it now and slooooowly think of any nice experiments you will do with it when it arrives

Received today, 95g KI

Sulaiman - 13-9-2018 at 04:26

The KI arrived this morning, it looked a little damp and felt underweight.
The KI that arrived weighed 95.55g but actually weighed 95.07g after drying,.
5% underweight... OK for the price if it is pure KI ... tbd.

Tdep - 26-11-2018 at 02:23

So I ordered some of this potassium iodide. Its only $6!
It took a while to turn up. And when it did arrive, it is completely unlabelled. Sure fine, it was free shipping.
Its got some yellow spots through it. Faint, but they're there. Fine, that's okay, i'll do a recryst, it was only $6.
It also has a mild unpleasant smell. Very mild, but its there. Whatever, it'll come out in the recryst.
Have I put up with too much? Well, this is where I draw the line: it isn't even potassium iodide. Now that's not fine, even if it was only $6!

I'm trying to titrate my ozone generator. Get out the new KI, make a standard solution, run it.... nothing. Add some other (more expensive) NaI... instant reaction! Do it some more, run the ozone through a conc solution of the new, now unknown salt.... nothing. I can say with complete confidence that I have been sold a highly soluble salt that does NOT contain the iodide ion in any concentration.
Looking at it now I can feel it is not dense enough.
Oh well, guess I only tipped $6 down the drain....

DavidJR - 26-11-2018 at 02:37

I forgot to report back on this. I also ordered from this listing. I tried to use this new KI for peroxide testing of ethers but I didn't get any reaction to my hydrogen peroxide control sample. I tried the exact same technique with known-good KI and it worked fine.

JJay - 26-11-2018 at 03:03

I never actually got mine... they canceled my order and refunded my money.

Ubya - 26-11-2018 at 05:19

well, i got mine and did not test it, if many here received something other than iodide i should really test it

[Edited on 26-11-2018 by Ubya]

woelen - 26-11-2018 at 05:39

This is sad to read. I ordered 300 grams from this seller (or a similar one, that may be the catch) and I had good experience with it (like CobaltChloride). I tested it immediately on arrival by taking some of the salt, dissolving it in dilute HCl and added a little 10% H2O2. I immediately got a grey precipitate of iodine in this reaction. So, apparently the sellers have different batches, some of them being OK, others not OK. This is the risk of buying cheap stuff from China. Up to now I have been lucky with chems from China, with electronics I once had inferior components, with lower gain and inferior parameters (e.g. transistors with low beta-factor and higher than tolerated resistance).

Half a year ago I also purchased 250 grams of elemental iodine from China for a little over EUR 20 with free shipping. I received it in a plastic brown bag, which was wrapped in another vacuum sealed bag, made of laminated plastic/aluminium. The iodine was fine though, I rebottled it. It leaves no residue on strong heating.

If you don't get what you pay for you either get a refund from the seller, or from eBay.

JJay's link and CobaltChloride's link are different. Could that be the difference in experiences?

[Edited on 26-11-18 by woelen]

DavidJR - 26-11-2018 at 05:55

Quote: Originally posted by woelen

If you don't get what you pay for you either get a refund from the seller, or from eBay.

JJay's link and CobaltChloride's link are different. Could that be the difference in experiences?

To clarify I ordered from JJay's link.

The problem with getting refunds is that often when it arrives from China after a couple of months, I don't have time to test it right away, so by the time I realise it's fake, it's too late.

Loptr - 26-11-2018 at 06:07

I also ordered from JJay's link and received my order fairly quickly. This was very early on, about as soon as I saw this thread. I just stowed it away in the back of my cabinet, but now I am thinking I need to test it.

Sulaiman - 26-11-2018 at 06:29

I have just returned from my lab after quickly testing a sample of my 100g ... pass

Solubility was indistinguishable from a known good sample, side-by-side.
I diluted the two samples then adding drops of silver nitrate solution alternately to each sample produced similar light yellow 'clouds'
If it is not KI then it is an excellent fake.
I've not tested the purity.

EDIT: Yes, I am dumb ... after reading posts below I realiseded that even sodium chloride would give a similar result.
I'll try to test it properly tomorrow.

[Edited on 27-11-2018 by Sulaiman]

DavidJR - 26-11-2018 at 09:56

I just tested mine again:

Flame colour reveals definite presence of sodium.
Dissolution of a spatula full in 15ml UP water, acidification with a small amount of HNO₃, and addition of 1ml 0.1N AgNO₃ gives a white precipitate. This precipitate dissolves on addition of a few ml of conc. NH₃

So. I've been sent some expensive table salt.

JJay - 26-11-2018 at 13:33

I would be furious. Sorry about that; I just thought the price was really good. Definitely request a refund....

Ubya - 26-11-2018 at 14:49

i'm really mad, it's not iodide, and it's not even a potassium salt, just sodium, most probably just fking table salt...
man i'm mad. fuck

WGTR - 26-11-2018 at 15:00

I’m guessing that y’all got sent iodized salt, at best.

[Edited on 11-26-2018 by WGTR]

JJay - 26-11-2018 at 16:17

Definitely contact eBay and/or the seller and complain. I don't know the seller and am not affiliated with them in any way (and they refunded my money), but if they are scamming people, they should be required to make amends and stop.

Deathunter88 - 26-11-2018 at 23:17

What's the average price of KI in the USA? I fail to see how $6 for a mere 100g is cheap. Here in China 500g of reagent grade KI is only $10 or so, and even a brand name is $20 for 500g, so I don't really see the incentive to sell fake KI, especially at such a high price.

Mr. Rogers - 27-11-2018 at 00:06

I bought 300g from the OP's link and, as someone stated, it was slightly wet but it's definitely KI.

It was shipped in a leaking plastic bag inside an envelope and the customs form said it was a necklace.

I think it's "fine" for the price.

[Edited on 27-11-2018 by Mr. Rogers]

Mr. Rogers - 27-11-2018 at 00:14

Quote: Originally posted by Deathunter88

What's the average price of KI in the USA? I fail to see how $6 for a mere 100g is cheap. Here in China 500g of reagent grade KI is only $10 or so, and even a brand name is $20 for 500g, so I don't really see the incentive to sell fake KI, especially at such a high price.

It's much more expensive in the US - probably 4-5x as much. Dunno why.

woelen - 27-11-2018 at 00:14

Average price where I live (EU) is appr. EUR 20 per 100 gram, so $6 (appr. EUR 5) per 100 gram is very cheap for us. Prices in the USA will not be very different.

Ubya - 27-11-2018 at 01:07

Quote: Originally posted by Deathunter88

if you can find a source that would sell internationally KI for that price we would be really happy

DavidJR - 27-11-2018 at 08:19

Quote: Originally posted by Deathunter88

I just looked at one of my suppliers in the UK and they have KI for £11.25/100g and NaI for £26/100g.

$6 US is about £4.70 at the moment. So yes, if it wasn't a scam, this would be very cheap for me.

S.C. Wack - 27-11-2018 at 15:51

Quote: Originally posted by Deathunter88

A price beyond competitive on amazon is $85/kg...best is $56/kg, for 5, which makes me wish I needed that much, that's insanely low. These are just repackers of probably Chinese goods. There are sellers of I, 50 g. for $10; technically, to import legally one needs a license from the DEA, which they won't provide.

Someone who has been pricing chemicals for a time might be suspicious of cheap imported iodide, and would want to test it well. Does China control some vast natural source of iodide? I suspect that the price from a non-Chinese source is higher than the amounts given above.

[Edited on 28-11-2018 by S.C. Wack]

Sulaiman - 6-12-2018 at 04:46

With the recently purchased potassium iodide I tried to precipitate the iodine using hydrogen peroxide and got an indication of low iodine content.

Today I made up a 500ml solution of what should be a 1.0M solution of the suspect potassium iodide,
(which I bought via eBay seller 94racing-au, the cheapest at the time)
and bubbled chlorine gas through 100ml of the solution
to replace the iodide with chloride and precipitate iodine.

36% HCl in a 3ml disposable pipette, TCCA in a side-arm test tube.

The crop of wet iodine on a 90mm diameter filter paper.

Ideally there should be 1/10th mole of iodine = 12.7 g
A little was lost to physical handling, and there should be a little Iodine in the filtrate/solution.
I guess that potassium chloride may increase the solubility of iodine in a manner similar to potassium iodide ?
Could anyone please tell me, or point to, or calculate,
the solubility of iodine in 1.0M Potassium Chloride ?
especially in the 10 to 20 Celcius range.

Result : 8.05g dry iodine

The filtrate has a strong yellow tint and the tissues used beneath the filter paper absorbed a lot of iodine giving a strong blue tint,
so I still suspect that KCl increases the solubilit of iodine in water..
Although the yield was only 63% I suspect that the KI was pure.
now I need to do a titration to be sure.

[Edited on 6-12-2018 by Sulaiman]

DavidJR - 6-12-2018 at 05:22

I just got a refund for my fake stuff.

Ubya - 6-12-2018 at 12:35

Quote: Originally posted by Sulaiman

I guess that potassium chloride may increase the solubility of iodine in a manner similar to potassium iodide ?

iodine is solubile in iodide solution because it forms triiodide, which is soluble

S.C. Wack - 6-12-2018 at 15:38

Quote: Originally posted by Sulaiman

I guess that potassium chloride may increase the solubility of iodine in a manner similar to potassium iodide ?
Could anyone please tell me, or point to, or calculate,
the solubility of iodine in 1.0M Potassium Chloride ?
especially in the 10 to 20 Celcius range.

You have the iodine, KCl is hopefully not a challenge...

So I looked in Mellor and he gives the exact answer actually and it's a good thing, because CA abstracts the same article but doesn't provide details...just like the publisher of Gmelin's didn't provide a pdf of any I volume for sale last time I looked...if you believe 1920 Gazz It, KCl accounts for less than 1/10 gram of the missing I.

[Edited on 6-12-2018 by S.C. Wack]

Sulaiman - 6-12-2018 at 16:41

Actually I would have to buy or make some KCl so the data is useful, thanks.
I dowloaded Mellor years ago but forgot the contents

After tidying up I dropped a pinch of TCCA into the filtrate,
I'll check for any precipitate tomorrow.

To be sure I'll boil dry the filtrate to dryness then heat the residue to see how much iodine vapour is produced.

I just realised that the iodine may have precipitated in particles too small to be caught by the medium filter paper that I used,
which now seems more likely than dissolution carrying the iodine into the tissues used beneath the paper for drying the iodine,
but if true then the light yellow colour of the filtrate should be much darker.
I'm confused.

S.C. Wack - 6-12-2018 at 19:26

The thinking was neutralizing HCl and K (bi)carbonate or hydroxide exactly should be a low hurdle.

IIRC H2O2/HCl and KI is popular enough that there were calculators for the different parameters, for meth cooks, who seemed satisfied. Perhaps with Cl as a gas, bad things are more likely to happen?

MrHomeScientist - 7-12-2018 at 10:22

I know for bromine it can form interhalogens with chlorine; that's why I avoided Cl when I made my Br. I wonder if something similar can happen with iodine.

UC235 - 7-12-2018 at 11:02

Quote: Originally posted by MrHomeScientist

I know for bromine it can form interhalogens with chlorine; that's why I avoided Cl when I made my Br. I wonder if something similar can happen with iodine.

ICl and ICl3 are well known. Bubbling Cl2 through iodide solution is how woelen made periodate.