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This article deserves GA status. It is well written, neutral, stable and well referenced with in-line citations (thus verifiable). The topic is clearly of top importance. There were minor problems with style, references and a few statements, and some facts had to be added. All that was fixed in the review process. Other editors are encouraged to further improve this article. Some of the old comments comments are listed below. Materialscientist ( talk) 09:36, 18 June 2009 (UTC)
1) Images are lacking. Suggestions: (i) Find a way to crop either
File:Osmium 1.jpg or
File:Osmium.jpg and put a cropped one into the elementbox. (ii) Remove
File:Platinum nuggets.jpg as poorly related to this article. (iii) Find interesting images. For example, electron micrograph demonstrating advantage of Os staining (unfortunately, I haven't got my pictures on that).
Materialscientist (
talk)
09:55, 12 June 2009 (UTC)
2) "Osmium forms compounds with the oxidation states ranging from 0 to +8" conflicts with the elementbox values.
Materialscientist (
talk)
09:55, 12 June 2009 (UTC)
3) Numbers 22562 ± 0.009 and 22587 ± 0.009 look wrong, and I would suggest converting into g/cm3.
Materialscientist (
talk)
09:55, 12 June 2009 (UTC)
4) I didn't notice a reference for staining.
Materialscientist (
talk)
09:55, 12 June 2009 (UTC)
5) Osmium easily oxidizes that should give it a tint. For example, is blue tint due to oxidation ? If so, please put it into the article.
Materialscientist (
talk)
09:55, 12 June 2009 (UTC)
6) Numbers are needed on crust abundance, and preferably on distribution (meaning what is the major form, osmium-rich alloys like OsIr or osmium-poor, and which ones. I think the article only talks about major deposits, not major compounds).
Materialscientist (
talk)
12:08, 13 June 2009 (UTC)
:The two largest sources for PGMs are the low sulfide platinum ores and the sulfide copper nickel ores. Large deposits of the first type are found in south africa, while the second type is the main source for PGMs in Russia and Canada. After leaching of the copper nickel ores with sulfuric acid at elevated temperatures and elevated pressure under oxygen the residuals contain most of the PGMs which can be extracted with chlorine and hydrochlric acid. The dissolved PGMs are extracted by ion exchange extraction. The polymeric ion exchange resin can be burned and the residual ash contains most of the PGMs, which are separated from each other by clasical methods or chromatography. The two PGMs Osmium and Iridium are the compounds with the lowest concentration in the leaching residues. For example the concentrate 2 has a content of 450g/t of platinum while the concentration of Iridium is 37g/t and of osmium 26g/t..
doi:
10.1595/147106704X1667.
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7) Please search (I will too) applications of osmium coatings. I think they were used to increase UV reflection, but abandoned because of oxidation.
Materialscientist (
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12:15, 13 June 2009 (UTC)
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help) UV spectrometers with osmium coated mirrors where flown in several missions also onboard the space shuttle, but it became clear that the atomic oxygen in low earth orbit is abundat enough to significantly deteriorate the osmium layer..
doi:
10.1364/AO.24.002660. {{
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A comment on the oxidation states. According to list of oxidation states of the elements, osmium can have not only all oxidation states from 0 to +8, but also oxidation state −2. -- Itub ( talk) 12:56, 12 June 2009 (UTC)