Talk:Boron nitride
From Wikipedia, the free encyclopedia
 |
Boron nitride is within the scope of WikiProject Chemicals, a daughter project of WikiProject Chemistry, which aims to improve Wikipedia's coverage of chemicals. To participate, help improve this article or visit the project page for details on the project. | ||
|
Article Grading: The article has not been rated for quality and/or importance yet. Please rate the article and then leave comments here to explain the ratings and/or to identify the strengths and weaknesses of the article.. |
|||
Contents |
[edit] disputed
There are several compounds harder than cubic boron nitride, most of which are nanocomposites. lysdexia 04:46, 24 Nov 2004 (UTC)
[edit] Graphite-like, diamond-like
I'd rather call it hexagonal and cubic. Maybe leave graphite-like as a remark, but the 'diamond-like' phase is cubic (contary to tetrahedal bonded diamond). Also in the Material-properties template under appearance the two modifications should be mentioned. --Dschwen 07:16, 12 Jan 2005 (UTC)
"Diamond cubic" is the name of the crystaline structure of most semiconductors, including diamond, BN, and SiC, and Si. Yes, the bonding is tetrahedral; in fact, tetrahedral symmetry is only found in cubic systems (look down the corner of a cube if you don't see the 3-fold axis at first).--Polyparadigm 23:27, 13 Feb 2005 (UTC)
[edit] Crystal structure
I find the use of the terms cubic and hexagonal ambiguous when applied to the carbon allotropes. Cubic close packing (ccp) and hexagonal close packing (hcp) are crystal structures derived from the closest packing of spheres to maximise space usage (74%). Diamond is composed of two interpenetrating ccp lattices. Graphite is not a close packed structure. However, graphite is composed of layers of fused hexagonal sheets.
[edit] "Ingestion" changes
I noticed a "not hazardous" note next to the "Ingestion" label in the table, and deleted it, assuming this referred to transportation regulations or something else. After a brief search of the web, I was not able to reach a definitive conclusion with regard to safety, as the web pages I looked at seemed to be somewhat contradictory. Perhaps someone with experience and knowledge on the safety of boron nitride can update this appropriately. Does anyone know what the "not hazardous" note refers to?--GregRM 18:53, 2 May 2006 (UTC)
- It's chemically inert, at least the diamond- and graphite-like allotropes, so it's non-toxic. The fullerene-like allotrope might be bad for you, though. —Keenan Pepper 19:30, 2 May 2006 (UTC)
- If you're really interested, google "boron nitride MSDS". Most of them either say "no effects" or at worst "irritant", which just means it's an abrasive. —Keenan Pepper 19:34, 2 May 2006 (UTC)
[edit] Comparison with recent borides?
Should we list other ultrahard boride compounds in "See Also"? Apparently Rhenium Diboride and Boron Aluminum Magnesium (BAM) Materials rank highly. Not sure if BAM is the preferred term. Does anyone have a broader perspective? —Ahazred8 07:45, 21 April 2007 (UTC)
[edit] h-BN sheets not quite planar?
I made the crystal structure images that appear in this article, but recently I heard that hexagonal boron nitride (h-BN, graphite-like) is not entirely planar, despite most textbooks and all the structural papers I could find (e.g. Pease) saying it is planar.
Does anyone know of a more recent structural determination with pyramidal nitrogens?
Ben (talk) 19:29, 28 March 2008 (UTC)
[edit] New infobox
I'm adding a Template:Chembox new to the article, so I'll put the old one here for reference.
Ben (talk) 20:16, 28 March 2008 (UTC)
| General | |
|---|---|
| Name | Boron nitride |
| Chemical formula | BN |
| Appearance | White solid |
| CAS Number | 10043-11-5 |
| Physical | |
| Formula weight | 24.818 g/mol |
| Melting Point | 2967 °C |
| Boiling point | 3273 °C |
| Density | 2.18×103 kg/m3 |
| Crystal structure | hexagonal or tetrahedral-cubic |
| Solubility | insoluble |
| Thermochemistry | |
| ΔfH0gas | 476.98 kJ/mol |
| ΔfH0solid | -250.91 kJ/mol |
| S0gas, 1 bar | 212.36 J/mol·K |
| S0solid | 14.77 J/mol·K |
| Heat of fusion | 3263.8 J/g |
| Safety | |
| Risk phrases | R36 R37 |
| Ingestion | ? |
| Inhalation | ? |
| Skin | ? |
| Eyes | ? |
| More info | ? |
| SI units were used where possible. Unless otherwise stated, standard conditions were used. | |
[edit] BN gem?
Why isn't this chemical used as a Diamond_simulant? Since learning about the atomic structure of this in school long ago, I thought it would be really cool to have a boron nitride ring rather than a diamond one. —Preceding unsigned comment added by 141.243.60.12 (talk) 01:02, 30 April 2008 (UTC)
