Talk:Dubnium/Archive 1

Archive 1

Talk

Evidence??

Text says:

This relatively high stability compared to the surrounding elements on the periodic table gives evidence that by manipulating the number of neutrons in a nucleus, one can alter the stabilities of such nuclei.

I say: why is that an issue? I thought it was proven since early 20th century. Maybe the text intends towards the island of stability? Rursus 21:22, 30 November 2006 (UTC)

Former contradiction (now fixed since anno dazumal)

The first sentence of the history section contains a contradiction:

"Dubnium ... was reportly first synthesized in early 1970 by Albert Ghiorso in Dubna..."

Ghiorso worked in Berkeley. I suspect that this sentence is a compromise between the two competing versions of the history of the discovery:

1) the element was discovered by Ghiorso in Berkeley

2) the element was discovered by Flyorov in Dubna

--Anon

Fixed. Thanks for the note. --mav

Halflife error

Couldn't find anything about this 268Db having a halflife of 29h, except this link: Fig Branch, whose text happenstance is the same as that of this article. Halflife of 29h seems to be a grave error. I'll soon correct the text... 268Db has been extrapolated to a half life of 6h acc2 nutab03, but that is an extrapolation. I'm going to try to find 268Db from research published on the net. If that fails, the halflife is guessed to be 6h, nothing else. Said: Rursus ☻ 16:31, 1 June 2008 (UTC)

Correcting myself: there are about 15 sources on Google claiming 268Db hl=29 h, all of them being copies of Wikipedia. Still searching. Said: Rursus ☻ 16:39, 1 June 2008 (UTC)

This link is pretty trustable:

Superheavies extend periodic table to 115

It's a little oldish, from 2004, it says 16 hours. The half life might have been remeasured since then. I'm going on. Said: Rursus ☻ 16:45, 1 June 2008 (UTC)

I decide that that link actually refers to research. The halflife of Db268 is 16 hours, there are a few sources (except wikipedia and imitators) claiming 32 h, but not 29 h. Said: Rursus ☻ 16:59, 1 June 2008 (UTC)

Not ready yet, I found one source for 28 h, but that's based on the sole 3 nuclei ever produced, article in 2007 (fresh). Said: Rursus ☻ 17:45, 1 June 2008 (UTC)

Here:

Data from XU_187225_1.ens

Said: Rursus ☻ 17:46, 1 June 2008 (UTC)

The oldest value is the 6h extrapolation, then came 16h (by Oganessian et al. 2004), then a tentative 32h (2005, M. GUPTA, THOMAS W. BURROWS??) and a current value of 28h (S. Geraedts and B. Singh (McMaster), 2007). Said: Rursus ☻ 18:17, 1 June 2008 (UTC)

Untitled

Article changed over to new Wikipedia:WikiProject Elements format by maveric149. Elementbox converted 10:23, 15 July 2005 by Femto (previous revision was that of 14:48, 12 July 2005). 12 July 2005

Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory - Dubnium.

Data for the table were obtained from the sources listed on the subject page and Wikipedia:WikiProject Elements but were reformatted and converted into SI units.

---

Liam Morland

I've reverted the discoverer back to an old state "Russian scientists" and not "Liam Morland".

• There's no evidence, except for that derived from Wikipedia that it was discovered by Liam Morland
• It had no citation
• The edit was made by an IP which has only made four edits, each changing inappropriate things to say "Liam Morland".

I think that means that it's overwhelmingly likely to be vandalism. If not, then apologies Liam! 131.111.21.21 (talk) 19:35, 22 May 2009 (UTC)

infobox

I've removed from the infobox: |- ! style="text-align:right;" | ²⁶¹Db | style="text-align:center;" | syn | style="text-align:right;" | 1.8 s | α | style="text-align:right;" | ²⁵⁷Lr |- ! style="text-align:right;" | ²⁶⁰Db | style="text-align:center;" | syn | style="text-align:right;" | 1.5 s | α | style="text-align:right;" | ²⁵⁶Lr |- ! style="text-align:right;" | ²⁵⁹Db | style="text-align:center;" | syn | style="text-align:right;" | 0.5 s | α | style="text-align:right;" | ²⁵⁵Lr |- ! rowspan="2" style="text-align:right; vertical-align:middle;" | ²⁵⁸Db | rowspan="2" style="text-align:center; vertical-align:middle;" | syn | rowspan="2" style="text-align:right; vertical-align:middle;" | 4.4 s | 67% α | style="text-align:right;" | ²⁵⁴Lr |- | 33% ε | style="text-align:right;" | ²⁵⁸Rf |- ! style="text-align:right;" | ^257mDb | style="text-align:center;" | syn | style="text-align:right;" | 0.76 s | α | style="text-align:right;" | ²⁵³Lr |- ! style="text-align:right;" | ^257gDb | style="text-align:center;" | syn | style="text-align:right;" | 1.50 s | α | style="text-align:right;" | ²⁵³Lr |- ! rowspan="2" style="text-align:right; vertical-align:middle;" | ²⁵⁶Db | rowspan="2" style="text-align:center; vertical-align:middle;" | syn | rowspan="2" style="text-align:right; vertical-align:middle;" | 1.6 s | 70% α | style="text-align:right;" | ²⁵³Lr |- | 30% ε | style="text-align:right;" | ²⁵⁶Rf

Nergaal (talk) 18:11, 25 March 2011 (UTC)

Density

Hello,

Is the estimated density really 39 g·cm^—3? This is nearly twice that of other heavy elements... Yann 23:21, 1 June 2007 (UTC)

Also, what's the source for this number? Both of the two sites linked at the bottom of the page either don't give a density, or say "no data". Unless there is a reliable source, this should be simply omitted. Kingdon 14:51, 4 June 2007 (UTC)

This edit. Unsourced, removed. Femto 16:12, 4 June 2007 (UTC)

In case anyone is still looking at this section, the actual predicted value is 29.3 g·cm⁻³: I added that a few years ago, of course with a citation. Double sharp (talk) 20:34, 14 March 2015 (UTC)

Pronunciation file

The sound can't be hardly heard with maximum volume. --2.245.181.136 (talk) 20:30, 18 August 2015 (UTC)

Chemistry of dubnium

Here's a recent paper from last year. (Also, I would've kept the old chem section around till its replacement was written. It was certainly unreferenced, but it was at least accurate.)

Thanks!

I didn't keep the old chem section not only because it was unreferenced; also because the extrapolated chem did read like OR and the more or less confirmed content made very little space.--R8R (talk) 12:03, 12 October 2016 (UTC)

I see your point, but to me an element article without chemistry and just with history is like presenting a biography that simply lists important dates and says nothing about a person's major accomplishments, so I wouldn't have wanted it like that even temporarily. For such an element it also gives the impression that chemistry is unknown, which while plausible is not true anymore. After all, note that atom-at-a-time chemistry techniques have improved to the point that out of the 118 known elements, the first 115 are accessible to chemistry under current methods (the last three just don't have long-lived-enough isotopes), and it's just that no one's gotten around to chemically characterising Mt, Ds, Rg, or 115. (113 has been experimented upon, but the results were not conclusive.) Double sharp (talk) 07:54, 13 October 2016 (UTC)

I'll get to this, but in meanwhile, you're free to restore portions of that section or even the whole thing if you like.--R8R (talk) 19:10, 14 October 2016 (UTC)

OK, I've temporarily restored it (to be removed once the replacement goes live). Double sharp (talk) 05:02, 15 October 2016 (UTC)

Also, "[e]lements 108–116 are expected to be partially very noble metals". (Though element 112 has also been predicted to be a semiconductor, and element 117 may be a semimetal.) Double sharp (talk) 10:15, 12 October 2016 (UTC)

Copyright violations

Please note that additions to WP articles must not violate WP:CPVIO, as the additions by User:R8R Gtrs appear to do. Kbrose (talk) 14:12, 3 December 2016 (UTC)

I am well aware of the rule and always try to abide it with the text visible in the Read mode. Thanks for your concerns, though. I've Made further changes to make sure no violations took place. (minor: Also when undoing edits pls don't revert what could not be considered wrong.)--R8R (talk) 14:19, 3 December 2016 (UTC)

Sources for recent (2000 onw.) experiments

2005: 115 -> 105 + 5 alphas, +5 state confirmed

same story in 2016; new techniques come into play

review of quesous studies of Rf and Db, 2016

--R8R (talk) 19:48, 28 December 2016 (UTC)

I changed the quality scale assessment to B-class now. Once the recent experiments are included, GA and FA (is there that much of a difference for an element like this, other than phrasing?) are easily within reach. Double sharp (talk) 12:57, 5 January 2017 (UTC)

More links:

review on recent experiments on elements 104 through 106

more experiments with aqueous HF

something else

--R8R (talk) 16:27, 10 January 2017 (UTC)

I have finally read these sources.

Now to sum it up:

There were a few experiments to cover: 2005 Russian-American experiments (115 -> 105 + 5 alpha), covered in detail in (1) and summarized in (4); 2006 Russian-Swiss experiments described in (5); and Y. Kasamatsu et al., Chem. Lett. 38, 1084 (2009) summarized in (3). I also get it that the Norwegians also did something with their SISAK but I can't find any good reports on what they did.

This must be a complete summary of what's been conducted by now.--R8R (talk) 13:49, 16 January 2017 (UTC)

Production of Dubnium 268

Dubnium 268 is listed on the isotope table but there is no mention of its production. —Preceding unsigned comment added by 71.229.45.155 (talk • contribs)

It is produced as the quintuple alpha daughter of ²⁸⁸Mc, but in future one could conceivably get a higher yield of it from transfer reactions like ²³⁸U+²⁴⁸Cm. Double sharp (talk) 07:58, 9 May 2017 (UTC)