Talk:Tantalum carbide

Reference

 * --Stone (talk) 08:57, 25 October 2008 (UTC)
 * --Stone (talk) 09:21, 25 October 2008 (UTC)

Hardness - Is it harder than diamond
There is a contridiction to the diamond article which states that diamond (including hyperdiamond) is the hardest material known. One must be wrong, and I believe it is this one. I do not not have the book mentioned but would go as far to say that if it does state that tantalum carbide is harder than diamond it is an error. —Preceding unsigned comment added by 132.181.210.231 (talk) 06:59, 31 August 2009 (UTC)
 * John Emsley's Nature's Building Blocks ANA-Z guide to the elements is a very authoritative reference. The statement on the diamond page is unreferenced. I have corrected both the diamond page and this page. Folk wisdom is not a reliable source for Wikipedia.--Ben Best (talk) 20:47, 6 October 2009 (UTC)
 * That book is by no means authoritative on diamond and hardness and it does not quote a source for its hardness statement. Reading the other literature does not confirm the claim. Please understand that there were dozens of claims of materials harder than diamond recently, some even published in highest-ranking scientific journals, but all quickly dismissed later. Materialscientist (talk) 22:15, 6 October 2009 (UTC)

Crystal Symmetry
The main article lists TaC0.5 as having two structures both of hexagonal symmetry. The space group of alpha-TaC0.5 (CdI2 structure) is correctly listed as P$\overline{3}$m1 which clearly puts alpha-TaC0.5 in the trigonal crystal system (see: http://en.wikipedia.org/wiki/Space_group). Similarly, (zeta-)TaC0.75 is in the space group R3m (as listed on this page) which is also trigonal although the article lists it as hexagonal. The article correctly lists beta-TaC0.5 as hexagonal.
 * The space groups were correct, but not the description. Revised. Materialscientist (talk) 23:44, 13 June 2011 (UTC)

The crystal "type" of the hexagonal form of TaC0.5 is listed as NiAs. The correct structure description appears to be the L'3 structure, as noted in reference #5. This structure is a regular HCP array of metal atoms with the carbon atoms occupying 1/2 of the octahedral interstices in the metal HCP structure. The carbon lattice has no long range order. — Preceding unsigned comment added by 198.102.153.2 (talk) 22:48, 14 June 2011 (UTC)
 * Corrected further. Thank you. "NiAs" was copied from our database; indeed, both refs 5 and 6 say there is no long-range order on C. Interesting is that many authors consider the P3m1 group as hexagonal. Materialscientist (talk) 23:44, 14 June 2011 (UTC)

What metallic conductivity
Can we have a value of electrical conductivity or resistivity (with source), and a temp-coefficient (with source), to characterise the "metallic" conductivity ? - Rod57 (talk) 11:38, 25 October 2021 (UTC)
 * Preparation and characterization of tantalum carbide (TaC) ceramics Nino. 2015 says "The electrical resistivity of the TaC ceramic was 0.36 μΩ m at 20 °C and increased linearly with temperature. The thermal conductivity of the TaC ceramic, 27.9 W (m K)− 1 at 25 °C, increased with temperature." - I'll try to add some of that. - If I'm reading the list in electrical resistivity right, TaC resistivity is between Galinstan and titanium. - Rod57 (talk) 12:46, 25 October 2021 (UTC)