Talk:Material properties of diamond

message: First, is there are reason Mechanical properties aren't included in this page.   E.g.  Compressive Strength / Tensile strength?   If not it would be nice to see them added.
Second, will someone please fix or remove the link on the ballas diamonds, it currently takes you straight to Grand Theft Auto.  --64.216.141.135 20:40, 1 November 2005 (UTC)
thread_title:  Some questions 

message: I may be wrong, but is buckminsterfullerene not harder than diamond...?
It would help if you could provide a source.
In general, the strength or hardness of a material 
depends on the size of the sample, and the temperature and pressure.
If you measure the hardness of a sample with only 60 carbon atoms,
you may get very different results than if you measure the hardness
of a 1 carat sample (containing 10^22 carbon atoms).
For instance, a collection of molecules (each of which has 60 carbon atoms)
may be a liquid.
Whereas diamond is solid at Standard Temperature and Pressure.
By the way, what is the melting point of buckminsterfullerene?
Unfortunately i am unable to find an Internet based source for this, but i have heard this from many sources, although they may be inaccurate. If anyone can help...
:::The sources provided in the article presents a modified form of a fullerene, ultrahard fullerite, it may not be naturally occuring. What it does link to is an academic paper, which provides infromation that shows that the engineered substance can under these circumstances, scatch diamond. Though it is physically harder than diamond, Ultrahard fullerite is not made in meaningful enough quantities or avaible in these quantitis in order to be considered a naturally occuring material, if even a mineral. When larger quantities are avaible, we can learn if the microscopic hardness translates to a macroscopic hardness harder than diamond, something meaninful given the current industrial usages of diamonds. --02:19, 21 Jan 2005 (UTC)
replies: text: I've already responded to most of this at Talk:Diamond#Can't be scratched?, but I'll point out again that the authors of that alarmist page have confused hardness with toughness. If you had read this article, you'd see that diamond's fragility is no secret. The pop-top claim is false; as for osmium (a metallic element, not a mineral), it comes in at only a 7 on Mohs' hardness scale. Your "Awesome Osmium" link again commits a serious lapse in understanding. It is confusing hardness with compressibility. In this respect, osmium is less compressible ("stiffer") than diamond, but certainly not harder. Here's the background information from bnl.gov (PDF file). -- Hadal 03:27, 13 Jun 2005 (UTC)
replies: text: Thanks for the information and the PDF.  [NiceIce, Osmium questions were mine]  61.229.125.147 16:13, 26 Jun 2005 (UTC)
thread_title:  Hardest naturally occurring mineral? 

message: What is the transmissivity of diamond (for specified wavelength(s))
through diamonds of specified type, specified color grade(s), and negligible flourescence?  An answer that could be converted to units of [percentage of light transmitted through a straight diamond path 1 centimeter long] would be very nice.  This would help answer the questions of how Diamond Color affects brilliance and optimum cut. -- Jasper 18:31, 19 November 2005 (UTC)
thread_title: Optical properties

message: When the article says that you can dope with Boron to obtain a p-type semiconductor but n-type hasn't been fabricated (or found) wouldn't Nitrogen-doped diamonds (yellow) be n-type semiconductors?
:Making sufficiently conducting n-type diamond is an open problem. If you dope with nitrogen (or rely on the often naturally incorporated nitrogen), the donor activation energy is very high, at about 1.7 eV (c.f. 0.4 eV to activate boron acceptor dopants), i.e. very few free electrons are created at room temperature. If you move down the periodic table to phosphorus, the activation energy is much lower, at 0.6 eV. Note, though, that it took about 10 years to successfully get active P into diamond. Moving down the table once more, arsenic should have an activation energy of about 0.3 eV, according to theoretical calculations (disclaimer: my theoretical calculations; see my thesis). However, it will be extremely difficult to get the large arsenic atoms into diamond's tight lattice in such a way that they are actually electrically active; most of the time, they will complex with lattice vacancies and be essentially useless. --Steve Sque (I'm mentioned in the references of the main article) --Sque (talk) 17:04, 15 April 2008 (UTC)
thread_title:  Electrical Properties of Diamond 

message: Does diamond have a boiling point?
List of elements by boiling point lists it, on the other hand, this temperature is not mentioned in this article. --4096 tavua (talk) 14:12, 31 January 2010 (UTC)
replies: text: Yes, but only at high (tens GPa) pressures. See phase diagram in carbon. Materialscientist (talk) 01:39, 1 February 2010 (UTC)
replies: text:  Doesn't boiling point of diamond require that there is liquid diamond? Doesn't diamonds chrystal break already when it melts? Or are we actually talking about sublimation point? --4096 tavua (talk) 08:05, 8 February 2010 (UTC)
replies: text: At ambient pressure it sublimates, at high pressures it melts into a liquid and then boils. Materialscientist (talk) 08:14, 8 February 2010 (UTC)
replies: text:  I'm starting to feel an idiot, but I have to get this clear. What is the difference, if any, between liquid carbon, liquid graphite and liquid diamond? If there is no difference, should we stop talking about boiling point of diamond, but talk about boiling point of carbon? Thanks for patience! --4096 tavua (talk) 09:26, 8 February 2010 (UTC)
replies: text: When they melt, they are same, but it takes different temperatures and pressures to melt graphite or diamond (or other forms of carbon) because of different arrangements between carbon atoms (different bond strengths). Materialscientist (talk) 09:32, 8 February 2010 (UTC)
replies: text:  So, there is no boiling point for diamond as such, am I right? The boiling point only applies to liquid carbon, not diamond, and it is a function of temperature and pressure. The melting point, however, depends of the starting solid phase as well. I went into this because there is much quoted web page that states not only that diamond can be boiled but also at what temperature it boils. This looks, pardon my French, insane to me. --4096 tavua (talk) 09:56, 8 February 2010 (UTC)
replies: text: Correct, in all aspects (including the French one :) Word diamond is traditionally exploited to attract attention - who cares about boiling graphite. Materialscientist (talk) 10:01, 8 February 2010 (UTC)
thread_title:  Boiling point 

message: Just a thought - but would it be worth having a section talking about the lattice constant of diamond - either in the Hardness and crystal structure section or only in the materials box.  I found a web ref for this - but not sure how good it is - probably I have a book at work with it in it somewhere.
http://www.siliconfareast.com/lattice_constants.htm
Lattice Constant at 300 K (Å)
Carbon (Diamond) - 3.56683  —Preceding unsigned comment added by Wideofthemark (talk • contribs) 13:46, 28 February 2010 (UTC)
replies: text: Added into the infobox. Materialscientist (talk) 23:42, 28 February 2010 (UTC)
thread_title:  Lattice Constant 

message: I haven't found it in the article.--Grondilu (talk) 08:25, 29 November 2012 (UTC)
thread_title:  Thermal capacity?