Talk:Didymium
From Wikipedia, the free encyclopedia
I was simply wondering, if didymium really was an element, would it have an atomic mass of the average of both praseodymium and neodymium's masses, or would it be something different? Venusium112 (talk) 23:25, 10 March 2009 (UTC)Millard P.S.
- That question is like asking "who would you be if neither of your parents had been born". DS (talk) 18:47, 9 April 2009 (UTC)
 | This article is rated C-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
| |||||||||||
Didymium can not be an element if it can be broken down. Since it contains the elemnts praseodymium AND neodymium, it is a compund. —Preceding unsigned comment added by 66.243.212.163 (talk) 00:57, 19 March 2009 (UTC)
Where does the "di" in didymium come from?
It seems strange that the prefix "di" is used in didymium. Presumably, didymium was believed to be a single element. As far as I know, no other element has an etymology that implies two of something. Yet as techniques improved, the single element didymium was the one that truly turned out to be double. Di is used in chemistry as dioxide or dibasic. In electricity and optics, for which lanthanides have unusual properties, there are terms like dichroic, dipole, and diode where the di means two. —Preceding unsigned comment added by 76.252.174.98 (talk) 04:28, 9 October 2009 (UTC)
I did some more digging. Encyclopedia Britannica, 11th edition, indicates that didymium derives from the Greek for twin, I read Britannica as reporting that the name didymium began to be used as the elemental twin of cerium. The main Wikipedia article suggests that didymium was the twin of lanthanum. I am sure that there was plenty of confusion with classification of rare earth elements at that time. In my mind, it will be that didymium was believed to be an element that was a twin of another element. The fact that it turned out to be a combination of two elements is coincidental. That is why the two meanings of the prefix "di" both apply. —Preceding unsigned comment added by 99.166.34.81 (talk) 03:51, 10 October 2009 (UTC)
Why is this article written like a children's story?
What's up with all the !'s and "funny" facts... someone fix this. Thanks. —Preceding unsigned comment added by 200.115.137.171 (talk) 15:43, 26 January 2010 (UTC)
Eye protection claims
If anyone wants a reference for the fact that didymium does not protect your eyes from IR, here is the absorption spectrum of didymium glass. Note that from about 900-1350nm, which is in frequency range known to damage the lens (800-3000nm), the transmittance is well above 85%.
https://aviantechnologies.com/wp-content/uploads/Didymiumfilter.gif Tkircher (talk) 03:57, 10 September 2022 (UTC)
- I don't see any claim in the article that didymium protects the eyes from IR; maybe that claim has been removed. I do see an assertion that didymium blocks 589-mm yellow light, followed by an unreferenced statement that "the usefulness of didymium glass for eye protection of this sort was discovered by Sir William Crookes." Who says the eye needs protecting from 589-mm yellow light? I do not believe that is a harmful wavelength. IR, yes (and didymium passes most of it). UV, yes (and didymium passes most of it). Violet and blue to some degree, yes (and didymium passes most of it). I can imagine that glasscrafters use didymium lenses because blocking the 589-mm yellow light makes it easier to see the glass they're working with under some conditions, but as the transmittancy graph shows, it offers no protection from known-harmful wavelengths. ~2025-34472-18 (talk) 23:21, 10 December 2025 (UTC)