Talk:Gallium
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Article changed over to new Wikipedia:WikiProject Elements format by maveric149. Elementbox converted 12:20, 1 July 2005 by Femto (previous revision was that of 17:27, 14 June 2005).
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[edit] Information Sources
Some of the text in this entry was rewritten from Los Alamos National Laboratory - Gallium. Additional text was taken directly from USGS Gallium Statistics and Information, the Elements database 20001107 (via dict.org), Webster's Revised Unabridged Dictionary (1913) (via dict.org) and WordNet (r) 1.7 (via dict.org). Data for the table was obtained from the sources listed on the main page and Wikipedia:WikiProject Elements but was reformatted and converted into SI units.
[edit] Talk
Discovery of the chemical elements says discovered in 1871. This article says 1875. -- Tarquin 10:23 Oct 5, 2002 (UTC)
- 1875 is the date given for the LANL, Elements database and Webster's Revised Unabridged Dictionary links above. Mendeleev predicted that this element exists in 1871. The discovery article is in error. I will fix it. --mav
Is the Most Stable Isotopes part correct? 31 and 39 do not make 71...
- Yeah - it is. They're not supposed to. Nippoo 13:59, 2 April 2006 (UTC)
[edit] Liquid elements
It is said here that gallium is liquid at room temperatures, like caesium, francium and mercury. In the "Rubidium" page it reads: "Rubidium is the second most electropositive of the stable alkaline elements and can be a liquid at room temperature". So, must it be added, or are there any missings? —The preceding unsigned comment was added by 200.55.116.210 (talk • contribs) .
- The Rb melt temp is 102.8 F = 39.3 C. Room temperature is not well-defined scientifically, but I think just about anyone would object to 103 F as room temperature. It's a good hot tub temperature. —The preceding unsigned comment was added by Sbharris (talk • contribs) .
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- Note also that some articles which mention liquid elements only refer to "near" room temperature, not "at" room temperature, to complicate things further. Femto 14:00, 16 August 2006 (UTC)
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[edit] diffusion
"Gallium also attacks most other metals by diffusing into their metal lattice — another reason why it is important to keep gallium away from metal containers such as steel or aluminum"[citation needed]
What was the first reason?
At what temperature does this occur - not at room temperature surely?87.102.33.144 12:22, 28 January 2007 (UTC)
- I don't know what the other reason is, but for some metals these processes can occur at room temperature (depending on thermodynamic stabilities of the alloys and the metals, some alloys have a reason to 'expell' a metal from the alloy (nickel from jewelry, e.g.), other alloys can be made by simply molding metals together at room temperature (Na/K-alloy, e.g). But sorry, no references available at this moment, I think a physical chemistry book would make a good reference for these processes. --Dirk Beetstra T C 12:45, 28 January 2007 (UTC)
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- Yes, another good example is dental amalgam.74.134.234.31 04:56, 19 May 2007 (UTC)
- I should make the comparison with zinc (as well as indium and aluminium) next to gallium in the periodic table - molten zinc doesn't seem corrosive at all to ferrous metals, and I can't think of a reason why gallium would be substantially different.87.102.33.144 17:20, 28 January 2007 (UTC)
- Gallium has a way lower melting point, and I am not sure whether in this case comparison to neighbouring elements will be true. We'll have to dig up some references for this. You could try raising the matter in wikiproject elements (see top of this talkpage, gives you a better chance of reaching people). See you around! --Dirk Beetstra T C 17:26, 28 January 2007 (UTC)
- I put in a referenc, it say something about diffusion!-Stone 23:04, 28 January 2007 (UTC)
- Gallium has a way lower melting point, and I am not sure whether in this case comparison to neighbouring elements will be true. We'll have to dig up some references for this. You could try raising the matter in wikiproject elements (see top of this talkpage, gives you a better chance of reaching people). See you around! --Dirk Beetstra T C 17:26, 28 January 2007 (UTC)
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I've changed the text to match what is actually stated in the reference-not some bullshit hot air from a wanker science student.87.102.2.226 12:02, 29 January 2007 (UTC)
- A simple google-search already easily yields quite some examples, I've added another one. --Dirk Beetstra T C 12:31, 29 January 2007 (UTC)
[edit] Hydrogen
Someone should add the application of Ga and Al for creating H for H power... When Gallium comes in contact with a metal it diffuses its chem lat. Al oxidizes extremely easy, but develops a protective film to make sure it doesn't erode. so adding Ga to Al disrupts the ability to develop film. if H20 is added the O oxidizes mit the Al and the H is left by itself... This H can then be used for H power... I'm to tired to write this better, Purdue U is where this process was developed so if you want to write it into the article find more info there... -Val Vaine Von Sarie
- Hg does the same. This method is not usefull, because the production of Al is more energy consuming than that of H2. To include this in the article would lead people to think that this method has a future use or is applied already.--Stone 08:54, 31 May 2007 (UTC)
Well, that's entropy; of course you can't get more energy out of the reaction than you put into it. That's only possible in nuclear reactions: fusion , theoretically, if we can ever get it to work, gives off far, far more energy than it takes to split water to get the hydrogen fuel to use in the fusion reaction.
The point is to use aluminum-gallium alloy as a way to store potential energy. You carry around pellets of the alloy in your car's fuel tank to react with water to liberate hydrogen from a tank of water on-the-go to use in a hydrogen fuel cell to generate electricity to power the electric motors in your car. The energy to refine the resulting aluminum oxide back into aluminum to use as a "battery" over again will, of course, need to come from elsewhere. This is useful to do because storing hydrogen is a pain. It seeps through any material over time and damages some metals as it does so: Hydrogen embrittlement. You can store pellets of aluminum metal alloy and water indefinitely--better than gasoline, as far as that goes. TheDragoon (talk) 10:13, 25 January 2008 (UTC)
[edit] Gallium probably not 1.5% of coal ash
The article says that some coal ash contains 1.5% gallium. I suspect that this information is bogus.
That number came from a brief mention in LANL's periodic table on the web. That's part of their "kids site", not a research result.
But sources that talk about commercial recovery of gallium from fly ash have far lower numbers. See U.S. Patent #4,686,031, "Beneficiation of gallium in fly ash", which talks about starting from concentrations in the 100ppm (0.01%) range. The state of West Virginia says that the mean concentration of gallium in West Virginia coals [2] is 6.45 ppm. Fly ash is more concentrated than coal, of course, because burning removes the carbon but leaves the non burnable minerals.
If fly ash, which is cheap and easily available from any coal-fired power plant, contained 1.5% gallium, that would be the major commercial source, and nobody would be bothering with extracting it from bauxite. But it's not. --John Nagle 17:53, 2 June 2007 (UTC)
- As I described here, there was a paper published around 1938 that indicated a figure of around 1.5% obtained from flue dusts from Northumbrian coal. If you can't find this article, let me know and I'll drive to another college to locate it for you. I spent several months looking at this problem - precisely because I could see the commercial potential (GaAs was just getting popular in 1982, when I did this work) - but I couldn't reproduce their numbers. (Then again, I was 22, and had virtually no experience of this type of chemistry.) Maybe I was misguided, but I didn't make up the numbers, and I got them from the original literature, and 1.5% matches exactly with what I remember. I also recall that other coalfields have very low levels of Ga and Ge. I didn't add the number into this article, so someone else must have used the same source I had. As I mentioned, germanium was isolated in huge amounts from this source around the 1950s, so the 1938 paper can't be all wrong. Please let me know if you find the paper, or if you need help with getting hold of it. Walkerma 16:31, 11 June 2007 (UTC)
- The article currently gives a 1.5% figure for fly ash generally, which is far too high, since the citations we have show far lower numbers. There may be a deposit somewhere with a higher concentration of gallium, and that should be cited as an unusual occurrence. --John Nagle 16:51, 11 June 2007 (UTC)
- Agreed. I suspect this coal seam may be unique. Walkerma 17:14, 11 June 2007 (UTC)
- The article currently gives a 1.5% figure for fly ash generally, which is far too high, since the citations we have show far lower numbers. There may be a deposit somewhere with a higher concentration of gallium, and that should be cited as an unusual occurrence. --John Nagle 16:51, 11 June 2007 (UTC)
[edit] Add the bulk/Young's modulus
Young's modulus can be calculated from the speed of sound in thin rods 2740 m/s by E = v^2*rho which gives 44.4 GPa.
The speed of sound should be determined from the pure deformation in one dimension - the longitudinal wave - and not with the eventual contraction of the material perpendicular to the wave motion as the Young's module derivation implies because that is not sound motion. It is a different kind of motion. This protest should also apply to the page on speed of sound.
Unless anyone protests I will add Young's modulus K=44.4 GPa.
What I really need is the bulk modulus. This is an important parameter because we are going to do pressure-volume work on solidifying expanding Gallium which means the bulk modulus is needed. Young's modulus can not be used.
I found this http://prola.aps.org/pdf/PR/v165/i3/p751_1 talking about the longitudinal sound speed to be 4070 m/s (at 1.3 K) giving a bulk modulus of K = v^2*rho=(4070^2)*5910 * = 97 898 559 000 Pa = 97.9 GPa. Worth adding? Density is probably different at that temperature too.
Maybe someone can find B.W. Magnum and D.D. Thornton, Metrologia 15 (1979), p. 201. That is an article on Gallium.
Davidjonsson 13:17, 7 August 2007 (UTC)
[edit] Wrong in applications, cooling, comparison to water
This "4.184/2.187 = 1.9 times more" is wrong. It should be "4.184/2.187 = 1.9 times less".
Another very important factor in cooling is the thermal conductivity which is much higher i Gallium compared to water. Gallium 40.6 W/m/K Water 0.6155 W/m/K
Gallium is a factor 66 better.
Davidjonsson 22:41, 8 August 2007 (UTC)
- Actually, that's what I thought till I did some maths on it. There's several problem with metals for cooling purposes. One subtle one is that to cool something you need to carry the heat away. With a liquid metal, if you flow metal past something, the heat tends to flow upstream which evens out temperature and reduces the heat flow into the metal. That and some other effects meant that the equations say that there isn't a big gain over water- and it wasn't as good as some oils. Basically that heat conductivity is not telling the whole story, you also need to consider viscosity, flow, heat capacity, and the thicknesses of one or two different boundary layers etc. etc. A factor of 66 better than water is simply untrue.WolfKeeper 05:13, 10 August 2007 (UTC)
- "4.184/2.187 = 1.9 times less".
The phrase "1.9 times less" is nearly meaningless. It is 2.187/4.184 = 0.5227 = 52% as much. Yes, the thermal conductivity should be taken into account. But all of this is NOR. We need a cite for it. SBHarris 04:00, 9 August 2007 (UTC)
NOR? Cite? All of it can be calculated. I adjust the obvious error. Davidjonsson 20:09, 9 August 2007 (UTC)
- NOR as in WP:NOR, standing for No Original Research. --Van helsing 20:57, 9 August 2007 (UTC)
- Concerning WP:CITE: "Editors may make straightforward mathematical calculations or logical deductions based on fully attributed data that neither change the significance of the data nor require additional assumptions beyond what is in the source". Was once part of WP:OR#What is not original research?, somebody found it to be a wise idea to delete it though. --Van helsing 21:09, 9 August 2007 (UTC)
- The problem is not in calculating simple ratios, as above. The problem is in using a ratio of thermal conductivities as a simple all-purpose "figure of merit" for a cooling fluid, assuming that a substance which has 66 times the thermal conductivity (a fact which is not original) is "66 times better" therefore, for a given application (an assertion which IS original). It's the last which isn't obvious. No engineering application is THAT straightforward. A better conductivity is one indicator only of performance, and it's not a perfectly quantitative one. SBHarris 04:24, 10 August 2007 (UTC)
- Concerning WP:CITE: "Editors may make straightforward mathematical calculations or logical deductions based on fully attributed data that neither change the significance of the data nor require additional assumptions beyond what is in the source". Was once part of WP:OR#What is not original research?, somebody found it to be a wise idea to delete it though. --Van helsing 21:09, 9 August 2007 (UTC)
[edit] Running out?
Just added the comment about running out of gallium. Checked the Indium element article where someone dismissed the same prediction for it as "scaremongering." I'm just including a scholarly reference here, not predicting! :) Maybe the same disclaimer can be found for gallium. Student7 (talk) 02:32, 5 May 2008 (UTC)
[edit] Deletion of price
I found the article with the following line:
The cost for 37.5 grams of gallium is 71.99.
I deleted this line for the following reasons:
The mass was not normalized. One gram or one pound would be preferred. The price lacked units. Is this dollars, pounds, yen or quatloos? There was no date. Prices change. There was no citation.
I think this is useful information, or rather it would be useful if brushed up a bit.Lon of Oakdale (talk) 21:30, 3 June 2008 (UTC)
[edit] Photograph of gallium melting in a gloved hand
Such a photograph appears in many high-school chemistry textbook entries on gallium. Is there a free one we could include here? I'm inspired by whoever turned the plain text entry in Oxygen#Compounds "Water is the most familiar compound of oxygen." into a caption for an excellent photograph illustrating that article. --arkuat (talk) 08:44, 4 June 2008 (UTC)
