Talk:Carbon

Template:Oldpeerreview Article changed over to new WikiProject Elements format by Bth and maveric149. Elementbox converted 12:58, 23 Jun 2005 by Femto (previous revision was that of 21:26, 22 Jun 2005 (http://en.wikipedia.org/w/index.php?title=Carbon&oldid=15686772)). Note: authoritative references for several infobox values (marked with question marks) are scarce and have not yet been fully integrated with the data pages. Femto 13:06, 23 Jun 2005 (UTC)

Contents

1 Information Sources 2 Talk 1 The Carbon Cycle 2 paragraph one 3 Crude oil VS petroleum :) 4 Removed mystery claim 5 Melting and boiling points? 6 Expansion and FA status

Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory - Carbon (http://periodic.lanl.gov/elements/6.html). Additional text was taken directly from USGS Periodic Table - Carbon (http://wwwrcamnl.wr.usgs.gov/isoig/period/c_iig.html), from the Elements database 20001107 (via dict.org (http://www.dict.org)), Webster's Revised Unabridged Dictionary (1913) (via dict.org (http://www.dict.org)) and WordNet (r) 1.7 (via dict.org (http://www.dict.org)). Data for the table was obtained from the sources listed on the main page and WikiProject Elements but was reformatted and converted into SI units.

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Talk

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Why isn't lampblack/soot/charcoal counted as an allotropic form of carbon? It is a form that is not diamond, graphite or a fullerene. Of course, it isn't crystalline, but that's not a requirement of being an allotrope.

--user:jaknouse

Aren't they just graphite with impurities? -- Tarquin 11:04 Jan 22, 2003 (UTC)

Does anyone know if carbon nanotubes are considered an allotrope or if they are just a subset of buckyballs? Iammaxus 03:34, 23 Dec 2003 (UTC)

All fullerenes. --mav

Concerning the following paragraph: "In its amorphous form, carbon is essentially graphite but not held in a crystalline macrostructure. It is, rather, present as a powder which is the main constituent of substances such as charcoal and lamp black (soot)." My field of research is amorphous carbon (a-C), and we define it as an amorphous matrix containing sp2 and sp3 hybridized carbon atoms. Depending on the sp2-sp3 ratio it has varying hardnes, opacity and electrical resistivity. We can synthesize a-C films which are transparent and almost as hard as diamond. Nothing like graphite or charcoal and no powder. There is an article on our lab webpage [1] (http://physik2.uni-goettingen.de/zope/faculty/4_ronning/crresearch/tac) --Dschwen 21:57, 20 Nov 2004 (UTC)

The Carbon Cycle

Carbon - in the form of differnet kinds of carbon-containing molecules - moves through an endless cycle. These are the stages of the carbon cycle. It begins when plants and algae remove carbon from the environment during photosynthesis. This carbon returns to the atmosphere via several carbon-cycle pathways.

A) Air contains carbon in the form of carbon dioxide gas. Plants and algae use carbon dioxide to make sugars, which are energy-rich, carbon-containing compounds.

B) Organisms break down sugar molecules me by plants and algae to obtain energy for life and growth. Carbon dioxide is released as a waste.

C) Burning fossil fuels and wood releases carbon dioxide into the atmosphere.

D) When organisms die, their carbon-containing molecules become part of the soil. The molecules are broken down by fungi, bacteria, and other decomposers. During this decay process, carbon dioxide is released into the air.

E) Under certain conditions, the remains of some dead organisms may gradually be changed into fossil fuels such as coal, oil, and gas. These carbon compounds are energy rich.

paragraph one

is the third bullet relevenat as an allotropic form of carbon ?!--82.213.33.76 22:22, 29 Dec 2004 (UTC)

no comments?? maybe a yes or a no ...tip,hint!--82.102.204.217 14:59, 1 Jan 2005 (UTC)

Crude oil VS petroleum :)

in the Applications section it is writte

Crude oil is used by the petrochemical industry to produce, amongst others, petroleum

but crude oil redirects me to article petrolium , does this make sence?!--82.102.204.217 15:17, 1 Jan 2005 (UTC)

Removed mystery claim

The discovery of a fifth form was announced on March 22 2004.

This claim followed a dubious classification of allotropes. I have no idea which allotrope was supposedly discovered in 2004; all the listed ones seem to have been discovered long before. --Andrew 03:55, Apr 13, 2005 (UTC)

Melting and boiling points?

The article currently claims that carbon sublimes instead of melting and also gives melting and boiling points. Clearly some information is missing. --Andrew 03:58, Apr 13, 2005 (UTC)

Missing... right now I'm having too much of it. I'm not an expert, but I've done a search for a phase diagram and adapted one for the article from a source (http://lbruno.home.cern.ch/lbruno/documents/Bibliography/LHC_Note_78.pdf) that appears to know what they're talking about—particularly because it mostly contains ranges and estimates, not concrete numbers. Those seem to be a little more tricky:

The CRC handbook 84th ed. gives:

• For graphite a sublimation point of 3825 °C.
• For diamond a melting point of 4440 °C at 12.4 GPa.
• For graphite a triple point at 4489 °C and 10.3 MPa.

And in the elements section:

• For carbon a graphite-liquid-gas triple point of "4492°C at a pressure of 101.325 kPa" ?!, and it sublimes at 3642 °C.

According to Amazon.com's search inside this book, the "4492°C at a pressure of 101.325 kPa" also is in the 85th ed.
According to [2] (http://www.speclab.com/elements/carbon.htm), the CRC 78th ed. apparently gave here:

• For carbon a melting point of ~3550 °C.
• Graphite sublimes at 3825 °C;
• A graphite-liquid-gas triple point at 4492 °C and 10.3 MPa
• A graphite-diamond-liquid triple point at (3830-3930) °C and 12-13 GPa

Lange's handbook, 15th ed. gives:

• For diamond a boiling point of 3930 °C.
• For diamond a melting point of 3500 °C at 63.5 atm.
• And graphite sublimates at (3915–4020) °C.

Huh.

I've put melting point="triple point, ca. 10 MPa<br />and (4300–4700) K" (from the diagram source), and boiling point="subl. about 4000 K" into the article, until somebody finds better data. Femto 12:28, 16 Apr 2005 (UTC)

Thanks! Wow. --Andrew 22:30, Apr 16, 2005 (UTC)

Expansion and FA status

Just an FYI - I'm thinking about expanding this article offline starting sometime next week and then submitting it to WP:PR and then WP:FAC. Once I start editing, I'll leave a note here and in an edit comment at the top of the article in order to reduce the chance of somebody else performing a significant expansion at the same time (minor edits/expansions are fine since those are easy to incorporate into an offline forked version). -- mav 03:57, 23 Apr 2005 (UTC)

I got distracted. Currently working on creating geology of the Delaware Basin. --mav 17:50, 2 May 2005 (UTC)