Talk:Metalloid

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Contents 1 Bismuth 2 Ununhexium 3 Conduction and valence bands 4 Bismuth is not a metalloid 5 Bismuth 6 There is another meaning for semi-metal, not equivalent to metalloid 7 Semimetal vs. metalloid 8 Aluminum is not a metalloid 9 "Metalloids" according to the American Chemical Society 10 Three undiscovered elements could be considered metalloids 11 What is the stairstep line called? 12 Just a small question

[edit] Bismuth

According to many textbooks, Bismuth is not a metalloid? AstroBlue403 6:19pm Feb 1st, 2006

Are you asking a question? From everything I've read, bismuth pretty much is the textbook example of a semimetal. eaolson 01:36, 2 February 2006 (UTC)

yoohhh, I was saying that in a lot of textbooks at our school, it says Bismuth is not a metalloid. I'm not sure, so I just put a question mark on the end. Still lots of homework to do, so I tried to make it fast on the last comment.AstroBlue403 11:46pm Feb 1st, 2006

• If you have an "official" definition of metalloid or semimetal, please feel free to put it up here, or even just the citation. Verifiability is always a good thing. I'm not yet convinced that metalloid and semimetal are exact synonyms, but haven't done significant research on it. I'm pretty sure that Bi is generally considered a semimetal, though. eaolson 20:35, 2 February 2006 (UTC)

[edit] Ununhexium

I've found nothing to suggest that ununhexium is a metalloid, am I missing something? Ctachme 17:35, 13 Aug 2004 (UTC)

Neither is ununseptium, according to its article. I've commented out both. Radagast 19:04, Feb 16, 2005 (UTC)

[edit] Conduction and valence bands

OK, I'll admit I'm a new editor, so I'm not quite sure how things work around here. Is it really true that there is no way of telling a metalloid from a semiconductor from a metal? What I've always thought was that metals have overlapping conduction and valence bands, semiconductors have a large bandgap and metalloids have a bandgap small with respect to kT. "Large" and "small" are fairly subjective terms, of course, but I've never heard anyone refer to silicon or germanium as anything other than a semiconductor, or bismuth as anything other than a semimetal.

Eric 22:28, 29 Jan 2005 (UTC)

[edit] Bismuth is not a metalloid

From what I've seen (in school textbooks) bismuth is always considered a metal. The Wikipedia article on bismuth states that it is a poor metal, which Wikipedia defines as "occuring between the metalloids and the transition metals". From this it seems that bismuth is, in fact, a real metal (though maybe not the best example of one!).

220.235.249.246 04:18, 10 February 2006 (UTC)

Agreed. Webelements.com describes all the metalloid elements as "semi-metallic", but Bismuth is described as "metallic". I'm for removing Bismuth from the list. Polonium is described as metallic too, though it is worth remembering that Chemistry is not black-and-white. CaptainVindaloo 22:26, 11 February 2006 (UTC)

I disagree. I am pretty sure that Bi has either a very small bandgap or that the conduction and valence bands overlap only indirectly. (I forget.) I will try to find some references as soon as I can. eaolson 22:49, 11 February 2006 (UTC)

On Monday, I'll check with my Chemistry teacher. CaptainVindaloo 23:02, 11 February 2006 (UTC)

[edit] Bismuth

There's some dispute about whether bismuth belongs on this page. I'm pretty convinced it does. I think part of the problem is that these are not hard and fast categories, but to some extent a matter of opinion. So it is possible for bismuth to be a poor metal, a heavy metal, and a semimetal.

From G. Jezequel, J Thomas, I Pollini. "Experimental band structure of semimetal bismuth." Physical Review B. 56. 6620 (1997):

The electronic properties of Bi, like those of the group-V semimetals, such as As and Sb, have been for a long time the center of the center of interest of many theoretical and experimenta investigations. Bismuth is a prototype semimetal..."

From J. Heremans et al. "Bismuth nanowire arrays: Synthesis and galvanomagnetic properties" Physical Review B. 61. 2921 (2000):

The galvanomagnetic transport properties of nanowires of the semimetal Bi...

From V. Edelman. "Electrons in Bismuth". Advances in Physics. 25. 555 (1976):

Studies of the electronic properties of bismuth are of interest, first, per se because of the intermediate position of bismuth between ordinary metals and semiconductors.

From an electrical standpoint, bismuth is very different from ordinary metals. So you can see why I feel it should be included in this section. eaolson 03:32, 11 March 2006 (UTC)

How about:

"Bismuth (Bi) also has some metalloid properties."

It definitely has some metalloid properties, and is in about the right place on the Table for a metalloid, but has some properties that may not be expected of a metalloid as well. CaptainVindaloo 00:32, 21 March 2006 (UTC)

[edit] There is another meaning for semi-metal, not equivalent to metalloid

In physics, a semi-metal is a material in which the density of states is zero at the Fermi level. Graphene is an example; the metalloids are not. The "Semi-metal" entry should be reinstated and reference this entry -- it should not be redirected to this entry, as it is now. Does anyone know how to undo a redirection? —The preceding unsigned comment was added by 70.231.194.19 (talk • contribs) .

When you use the redirect page (ie, you search for Semi-metal and get redirected to Metalloid) there will be a link at the top of the page saying "Redirected from Semi-metal". Follow the link back to the redirect page, which you can edit as a normal article. See Wikipedia:Redirect. CaptainVindaloo ^{t c e} 16:12, 7 June 2006 (UTC)

[edit] Semimetal vs. metalloid

I've been doing some research, and it seems to me that "metalloid" is used primary in the chemical sense and "semimetal" is used primarily in the electrical sense. I think metalloid is a more general term, referring to materials partway between metals and nonmetals, and semimetal has a more specific meaning, generally referring to something partway between a metal and a semiconductor. The best, most explicit definition I've found is from Burns's Solid State Physics, but unfortunately, there's no online version.

I've created a draft of a new article for semimetal, and would appreciate comments. I'll probably move this over to the actual semimetal article in a few days. eaolson 16:14, 11 June 2006 (UTC)

Ah! I realise why there is much ado about Bismuth now! Some people are looking at this as Chemists, others as Physicists. Chaos results.

The draft looks pretty good. Is there any way it could be illustrated, maybe? Diagrams? Are there any extensive listings of Semi-metal materials at all? Also, it might be an idea to add a notice to make sure anyone looking up either Metalloid or Semi-metal is getting the correct article (eg, getting the Chemical article when they want the Physical article). CaptainVindaloo ^{t c e} 17:31, 11 June 2006 (UTC)

I've added my draft article at semimetal and changed the "semi-metal" redirect. eaolson 00:27, 14 June 2006 (UTC)

[edit] Aluminum is not a metalloid

The 8 metalloids are Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Polonium, Astatine. "... the majority of known elements are metals; only 17 elements are nonmetals, and 8 elements are metalloids."(Chang, Raymond. 2005. Chemistry, Eight Edition.) Sorry, there is no direct quote saying Aluminum is not a metalloid. However there is a periodic chart showing the metals, non - metals and metalloids. It shows aluminum as a metal. —The preceding unsigned comment was added by 70.73.254.247 (talk • contribs) .

• Citation? eaolson 22:56, 15 October 2006 (UTC)

Yes please, a citation would be lovely, considering the amount of ruffled feathers over bismuth. CaptainVindaloo ^{t c e} 00:16, 16 October 2006 (UTC)

• Yeah, in my textbook, it says that Aluminum IS one. Ctifumdope 20:20, 16 October 2006 (UTC)

[edit] "Metalloids" according to the American Chemical Society

Check out the periodic table ACS provides at [1]. I don't know what the original source of their data is, but they give B, Si, Ge, As, Sb, Te, Po as metalloids, Be, Al, Ga, Sn, Bi as metals, and C, P, Se, I, At as nonmetals. Uuh has no designation; after Lr, they stop labelling the element as a metal/nonmetal (they stop specifying it as a solid/liquid/gas after Sg). youngvalter 02:21, 12 November 2006 (UTC)

I have edited the article to make it plain that "metalloid" is not a rigorous term, but just a useful general one for elements which show properties intermediate between "metals" and "non-metals", and that some allotropes of an element may be more metalloid than others. All these squabbles about whether bismuth is this or polonium is that are moot and just terminology quibbles.--feline1 11:22, 15 January 2007 (UTC)

[edit] Three undiscovered elements could be considered metalloids

Are elements 167, 168, and 218 are considered metalloids. I knew that element 117 is a metalloid [formerly a metal] while astatine is a nonmetal [formerly a metalloid], and aluminum is a metal even if placed next to a series with single metalloid by looking at the metals and non-metals periodic table. Group 3A is the only group that has just one metalloid--boron and just below it, a metallic aluminum, but boron is bordered at the top of the block. It is hard to predict if these elements should be considered metalloids by following periodic trends from top-left to bottom-right [staircase] of the p-block. Cosmium 03:24, 18 February 2007 (UTC)

The question is a bit pointless, as these elements don't exist - we've never found them in nature, no-one's yet ever managed to make them in a laboratory. So we could only speculate what they might be like, if they ever could be made. There's probably more chance of me winning the lottery than element 218 being discovered! :)--feline1 17:21, 19 February 2007 (UTC)

[edit] What is the stairstep line called?

Ok, so that line that is surrounding by metalliods is normally called the stairstep line. What is it really called? —Preceding unsigned comment added by Lrn121 (talk • contribs) 23:20, 6 November 2007 (UTC)

Try asking at WP:RD/S. Personally, I've only ever heard 'stairstep' used. CaptainVindaloo ^{t c e} 17:14, 7 November 2007 (UTC)

[edit] Just a small question

This article is practically a word-for-word reproduction of the first half of this article. The only thing I'm wondering is: who's copied who? Joelster (talk) 04:48, 9 April 2008 (UTC)

As the guy who wrote most of the sentences in the wikipedia article, I can tell you that "chemical-universe.com" copied wikipedia (in fact, mostly copied ME). B*stards.--feline1 (talk) 13:54, 9 April 2008 (UTC)

[edit conflict] It worried me at first, but after reviewing this article's history, I think we were here first, and they're WP:MIRRORing us. Take for example, the vaguely familiar first and second revisions (diff) from way back in 2002. A later revision in from 2004 (diff) again just looks like iterative progress, and looks very much like what we have today (diff), for instance in the use of the Greek translations. The same thing appears to have happened with Alkali metal[2]. Obviously, a few more eyes on this would be a good idea rather than relying on my opinion alone, but I don't think there's a need for panic here. Not too great on the GFDL front on their part, but it's not the end of the world. CaptainVindaloo ^{t c e} 14:15, 9 April 2008 (UTC)

Yeah, thanks for answering that. Man, they could at least put it in their own words! The website article on metalloids also seems to have copied (seems like another copy-and-paste job) the bullet-point summary from this article on about.com. Joelster (talk) 21:38, 9 April 2008 (UTC)

Someone should probably send a GFDL non-compliance letter, or drop a note at WP:AN. This kind of thing gives me the fear. CaptainVindaloo ^{t c e} 20:51, 10 April 2008 (UTC)