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woelen
Super Administrator
Posts: 7976
Registered: 20-8-2005
Location: Netherlands
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Mood: interested
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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]
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diddi
National Hazard
Posts: 723
Registered: 23-9-2014
Location: Victoria, Australia
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Mood: Fluorescent
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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]
Beginning construction of periodic table display
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woelen
Super Administrator
Posts: 7976
Registered: 20-8-2005
Location: Netherlands
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Mood: interested
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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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BaFuxa
Hazard to Self
Posts: 61
Registered: 18-9-2017
Location: Mars
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Mood: Buzzing
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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]
Potential counts for nothing until realized.
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wg48
National Hazard
Posts: 821
Registered: 21-11-2015
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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.
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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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NeonPulse
Hazard to Others
Posts: 417
Registered: 29-6-2013
Location: The other end of the internet.
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Mood: Isolated from Reality! For Real this time....
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| 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.
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NeonPulse
Hazard to Others
Posts: 417
Registered: 29-6-2013
Location: The other end of the internet.
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Mood: Isolated from Reality! For Real this time....
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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.
  
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wg48
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Registered: 21-11-2015
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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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diddi
National Hazard
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Registered: 23-9-2014
Location: Victoria, Australia
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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
Beginning construction of periodic table display
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woelen
Super Administrator
Posts: 7976
Registered: 20-8-2005
Location: Netherlands
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Mood: interested
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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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wg48
National Hazard
Posts: 821
Registered: 21-11-2015
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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.
Borosilicate glass:
Good temperature resistance and good thermal shock resistance but finite.
For normal, standard service typically 200-230°C, for short-term (minutes) service max 400°C
Maximum thermal shock resistance is 160°C
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DavidJR
National Hazard
Posts: 908
Registered: 1-1-2018
Location: Scotland
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Mood: Tired
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| 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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diddi
National Hazard
Posts: 723
Registered: 23-9-2014
Location: Victoria, Australia
Member Is Offline
Mood: Fluorescent
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@wg48
Name and Shame for the rest of us. There may be a pattern of deliberate cheap junk dumping.
Beginning construction of periodic table display
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wg48temp9
National Hazard
Posts: 761
Registered: 30-12-2018
Location: not so United Kingdom
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Too good to be true
I purchased a vacuum pump on ebay. A new Yellow Jacket brand two stage, very nice and very cheap at £13 including postage.
It did not arrive and when I checked the status the seller had given me a fake tracking number and was no longer on ebay and an other buyer had left
negative feedback with the sane problem and purchase.
Yes it was too good to be true. Fortunately ebay gave me a full refund.
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
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