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Author: Subject: Bad elements from ebay again
woelen
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[*] posted on 19-6-2018 at 07:11


I found another bad one:

https://www.ebay.nl/itm/100-grams-High-Purity-99-99-Antimony...

Attached you find the image, associated with this offer:

sb-99.999.jpg - 26kB

The description is: "100 grams High Purity 99.99% Antimony Sb Metal Lumps"


I ordered one of these, and as a remark with the order I wrote that if my analysis of the sample reveals that the purity really is 99.999%, that he could expect a larger offer from me in the future.

The sample was shipped to me the next day, and one day later I received a message where he told me that he had made a mistake and that the offer was wrong. He admitted that the real purity of the material is a little better than 99.9%, so it's just 3N instead of 5N. For most practical purposes this is pure enough, but it is good to know that you don't get the ultra high purity mentioned by the seller. In the object description he talks about 99.99% purity, but even that is not reached.
I strongly urged him to change the picture with the offer and to change the description to 99.9% instead of 99.99%. I'll let the order go on (it only is a small amount of money), but I will not give 5 stars feedback. These chinese sellers find their feedback very important and by providing less than 5 stars you can really punish them, even more so than having them refund the few dollars for the order.



[Edited on 19-6-18 by woelen]




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[*] posted on 19-6-2018 at 15:07


yes. when i challenged my seller about the Zn not being pure because it was covered in oxides, he dropped the purity to 4N, then in another reply, it was down to 3N. they are lying pricks and not worth supporting. "If it looks too good to be true..." as they say
I have found true 4N+ elements are very expensive. you just dont get the ultra high quality material from shitty processing facilities, so if you want a product from a multimillion dollar refinery, then you have to pay.

maybe one day there will be proper laws governing what people describe a product as, so that there is recourse and some form of sanction against sellers who peddle crap. and i dont just mean ebay. look at all the shonky businesses trying to extract cash from our pockets, from underdelivering telcos to wonder anti aging cosmetics that prey on peoples vanity. pfffft i hate it all.... (rant rant rant.......)

[Edited on 19-6-2018 by diddi]




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[*] posted on 19-6-2018 at 23:49


Yes, I know the huge price difference. I purchased red phosphorus, which was sold to me as 98.8% material (the balance being mainly white P). I had to pay EUR 55 for 1 kg of the material. It has quite a strong typical phosphorus smell.
At the same seller, later, I wanted a good sample for my element collection. He had 4N red P. I purchased 10 grams, and had to pay EUR 20 for this little amount! The material is odorless and that is quite special for red phosphorus.

Sometimes, however, you can be lucky with some unknown/shady seller and you can get really good stuff for just a few bucks. Especially if they sell old/unused materials from a decommisioned lab or something like that. In that way, I obtained 5N antimony, 30 grams for EUR 5 and I obtained 25 grams of 3N crystalline boron for just 7 euros.




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[*] posted on 20-6-2018 at 02:48


I tested 2 items that I bought from seller pickbestforyou, both did not match the description.

He tries to fight the obvious with obfuscation. He asked me twice to "check" on my order, took 5 days to get him to concede now he offers a partial refund which I refused.

Edit : I got a full refund from him without ebay intervening.


[Edited on 21-6-2018 by BaFuxa]




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[*] posted on 20-6-2018 at 03:20


NeonPulse:

Quote: Originally posted by NeonPulse  

Maybe they ran out of Mo powder and switched it up. Late last year I bought the exact same thing from this selller and it checked out to be Molybdenum. The powder was a dark grey nearly black and slowly dissolved into 31% HCl leaving a dark yellow greenish solution. Adding NaOH to that gave a black precipitation. Pretty sure I got the real deal. I had also bought Co, Cu, Ti and B powders from them with no problems. I probably won’t try my luck at eBay Ir powder though. Seems like others here have been ripped off with that. I guess it’s a roulette game.


As a check, for both of us you could try dissolving excess Mo in H2O2 to see if it eventually turns blue. If the reaction is very vigorous with powder you may have to cool the reaction tube to avoid thermal decomposition the H2O2.
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[*] posted on 21-6-2018 at 16:40


Quote: Originally posted by wg48  
NeonPulse:

Quote: Originally posted by NeonPulse  

Maybe they ran out of Mo powder and switched it up. Late last year I bought the exact same thing from this selller and it checked out to be Molybdenum. The powder was a dark grey nearly black and slowly dissolved into 31% HCl leaving a dark yellow greenish solution. Adding NaOH to that gave a black precipitation. Pretty sure I got the real deal. I had also bought Co, Cu, Ti and B powders from them with no problems. I probably won’t try my luck at eBay Ir powder though. Seems like others here have been ripped off with that. I guess it’s a roulette game.


As a check, for both of us you could try dissolving excess Mo in H2O2 to see if it eventually turns blue. If the reaction is very vigorous with powder you may have to cool the reaction tube to avoid thermal decomposition the H2O2.


I’ll try this this afternoon and post the results. I have some 35% H2O2 I recently acquired that will work fine. As for the HCl dissolving I did, only a very small amount of the powder I put in there dissolved and it took quite some time to do it. Here’s a picture I took at the time.

18FF6AE4-103B-4388-AA3B-64C6E22F9486.jpeg - 81kB




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[*] posted on 22-6-2018 at 19:59


Here’s the test I did on the supposed Mo powder. I added a small amount of 35% H2O2 to a test tube and added some of the metal to it. Immediately there was a very exothermic reaction which turned the solution a dirty green first then into yellow. Slowly I added more metal and after a short while the colour did turn to a brilliant blue much like Prussian blue.


6ACB5CDB-D932-4451-8774-BC1D79E04D4C.jpeg - 2MBA9667DC7-56F9-4C41-99ED-CEB72CC95FC7.jpeg - 1.8MBF7336368-092F-4845-A4B4-C6FCBAC9B6A6.jpeg - 2.9MB




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[*] posted on 22-6-2018 at 22:12


Thanks NeonPulse. That test confirms my observations about the reaction between H2O2 and Mo to produce the yellow MoO3 which can then be partially reduced by excess Mo to the intensely blue coloured mixed valencE oxide called blue Mo.

Is your blue Mo reoxidised back to MoO3 by air or H2O2?

I don’t have any W powder to check if W reacts so readily as Mo and produces the equivalent blue W. If that is the case we need a simple method to discriminate between Mo and W. Perhaps say Cu metal or an organic compound can reduce one of the trioxides to a blue but not the other.

Thinking about it I have some small filament bulbs I could extract the W filament from one to try to make blue W. I also wonder if a mixed Mo/W blue can be synthesised and if it has any novel properties.
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[*] posted on 23-6-2018 at 17:36


W is very slow to react with H2O2. i digest thoriated W electrodes in H2O2 and it takes ages. you get a pale yellow solution



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[*] posted on 24-6-2018 at 23:17


MoO3 is not yellow. Pure MoO3 is white (or very pale grey). The yellow color of hexavalent molybdenum in solution usually is due to some complex (e.g. with phosphate).

W slowly dissolves in aqueous H2O2. No acid needed, nor any other compounds, just H2O2 in water. The solution is nearly colorless.




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[*] posted on 19-7-2018 at 07:51


I ordered 2.5kg of sodium bisulphate from ebay UK £13 including postage, a good price (and just £17 for 5kg tub). But it arrived today as 2.5kg of iron sulphate or that’s what it says on the tub. Perhaps just a simple error. But I have had a run of incorrect or fake items of late. Hopefully I will get the correct item or a refund eventually.






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[*] posted on 19-7-2018 at 12:33


Quote: Originally posted by woelen  
I found another bad one:

https://www.ebay.nl/itm/100-grams-High-Purity-99-99-Antimony...

Attached you find the image, associated with this offer:



The description is: "100 grams High Purity 99.99% Antimony Sb Metal Lumps"


I ordered one of these, and as a remark with the order I wrote that if my analysis of the sample reveals that the purity really is 99.999%, that he could expect a larger offer from me in the future.

The sample was shipped to me the next day, and one day later I received a message where he told me that he had made a mistake and that the offer was wrong. He admitted that the real purity of the material is a little better than 99.9%, so it's just 3N instead of 5N. For most practical purposes this is pure enough, but it is good to know that you don't get the ultra high purity mentioned by the seller. In the object description he talks about 99.99% purity, but even that is not reached.
I strongly urged him to change the picture with the offer and to change the description to 99.9% instead of 99.99%. I'll let the order go on (it only is a small amount of money), but I will not give 5 stars feedback. These chinese sellers find their feedback very important and by providing less than 5 stars you can really punish them, even more so than having them refund the few dollars for the order.



[Edited on 19-6-18 by woelen]


Just checked that link and it appears that the seller has changed the product description to 99.9% now




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[*] posted on 20-7-2018 at 16:13


@wg48
Name and Shame for the rest of us. There may be a pattern of deliberate cheap junk dumping.




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