Talk:Rubidium/Archive 1

Effects of its radioactivity
I removed this sentence from the text:


 * However, taken in excess it can be dangerous, as it is slightly radioactive.

It's wrong because its radioactivity is so weak, that it has no noticeable effect.

A gram of rubidium has 6 * 1023 * 0.278 / 85 = 1.96 * 1021 radioactive atoms. Its half-time is about 1.54 * 1018 seconds, so each gram of naturally occuring rubidium has about 650 radioactive disintegrations/second. Each disintegration releases 0.283 MeV of energy, so that's 184 MeV released/gram/second.

Assuming an average person consumes some rubidium, one would absorbe 4 * 10-10mS/gram of Rb/second (might be an orders of magnitude higher), that's 0.01 mS/year, which is well below the 2.4 mS/year background radiation, let alone the 200 mS limit under which there is no statistically significant danger. bogdan (talk) 23:32, 28 March 2009 (UTC)

Precautions
Rubidium reacts violently with water and can cause fires. To ensure both health and safety and purity, this element must be kept under a dry mineral oil, in a vacuum or in an inert atmosphere.

I have heard it will form unstable peroxides when kept under mineral oil. Maybe that will not happen if dry, I don't know. —Preceding

Jokem (talk) 13:10, 10 April 2009 (UTC)

History: extraction of rubidium salts from mineral water by Bunsen
According to http://en.wikipedia.org/wiki/Caesium#History and the German language article on Rubidium, Bunsen discovered rubidium's spectral lines in mineral water and also processed 44,200l of it in order to extract about 9g of rubidium chloride. I haven't heard of him extracting it from lepidolite (despite the German source noted) and there is no mention of it on the German wikipedia or the (English) caesium article. Does anyone have more information on this?

In any case, I believe the information from the caesium article should be incorporated into this one. —Preceding unsigned comment added by 95.223.228.160 (talk) 03:58, 26 January 2010 (UTC)


 * Refs 2 states in the introduction that the caesium was found in the mineral water on the thid page it starts with:
 * Behandelt man sächsische Lepidolith nach einer der bekannten Bethoden, durch die Alkalien von den übrigen Bestandtheilen getrennt für sich in Lösung gehalten werden, und fällt man eine solche Lösung durch Platinchloride, so entsteht ein Niederschlag, der, im Spectralapparat geprüft nur Kaliumlinien erkennen läßt. Wird dieser Niederschlag widerholt mit kochenden Wasser ausgezogen und zwischendurch im Spectralapparat geprüft so zeigen sich zwei neue prachtvolle violette  ....... Wir schlagen daher für diese Alkalimetall, mit Beziehung auf jene besonders merkwürdigen dunkelrothen Spectrallinien die Benennung Rubidium mit dem Symbol Rb, .....

This makes it 100% clear that the first isolation was done from lepidolite. The article is written in a way that it does not give the time sequence of the discovery and in which sample the first rubidium or caesium was discovered by spectroscopy, but it is clear that Rubidium (1.1850 gramm of rubidium chloride) was produced from lepidolite and caesium from mineral water residues. The advantage of lepidolite was that it contains only traces of caesium. The extraction of the mineral water residues yielded the 9 and 7 gramms of rubidiumchloride and caesiumchloride. Which was more than from the lepidolithe, but it was hard to seperate the both. --Stone (talk) 07:21, 26 January 2010 (UTC)

Use in fireworks
I removed this sentence:

Rubidium compounds are sometimes used in fireworks to give them a purple color.

as rubidium is most definitively not used in any commercial fireworks (and it gives a red flame color, not purple). AFAIK it's not used in home-made fireworks either, but some idiot may have tried it. —Preceding unsigned comment added by 62.3.121.230 (talk) 00:20, 29 January 2010 (UTC)


 * Several idiots tried it and published it in an book and a peer reviewed journal. Pyrotechnic Chemistry and therefore I put it back into the article! --Stone (talk) 08:13, 29 January 2010 (UTC)

Origin of name
I doubt the statement about the origin of the name Rubidium being the colour of the flame. Most references speak of red spectral lines that the discoverers observed from flame spectroscopy. One web page that I found seems to include statements from them: http://web.me.com/dtrapp/Elements/color.html

On 23 February 1861 Bunsen and Kirchhoff reported that dissolving alkalies from lepidolite from Saxony, followed by precipitation by platinic chloride and repeated washing with boiling water, revealed two new spectral lines of a magnificent violet. Additional washing revealed red, yellow and green lines not belonging to other elements. Among them we may mention two remarkable red lines... located at the extreme red end of the spectrum...  (which) led us to give this element the name Rubidium and the symbol Rb from Rubidus (Latin) which, with the ancients, served to designate the deepest red.

Can someone locate something definitely authoritative as a reference? 199.247.253.43 (talk) 08:42, 23 March 2010 (UTC)

From the cited source of Bunsen:


 * ....Unter denselben sind zwei rothe dadurch merkwürdig, daß sie noch jenseits der Frauenhofer'schen Line A oder der mit dieser zusammenfallendedn Line Kaa, also im aller äußersten Roth des Sonnenspectrums liegen. Wir schlagen daher für diese Alkalimetall, mit Beziehung auf jene besonders merkwürdige dunkelrothe Spectrallinien die Benennung Rubidium vor mit dem Symbol Rb von Rubidius, welches von  den Alten für das dunkelste Roth gebraucht wurde....

--Stone (talk) 11:00, 23 March 2010 (UTC)

Oh, thanks. That was a quick fix. 199.247.253.42 (talk) 04:26, 24 March 2010 (UTC)

Assessment comment
Substituted at 05:01, 30 April 2016 (UTC)