Difference between revisions of "Carbon"

Revision as of 14:25, 1 June 2023

This article is a stub. It needs to be expanded.

sp³ allotropes:

sp² allotropes:

Graphite (today single cystallinge graphite is called HOPG for highly ordered pyrolytic graphite)
Future: POPMG for "perfectly ordered piezomechanosynthesized graphite.
Buckyballs (convex curvature; concave from inside) – weak molecular solids
Nanotubes (no curvature – flat rolled)
3D meshes (hyperbolic curvature)
"penta graphene" (cairo pattern)
...

No exactly defined structure:

Exotic allotropes:

Binary compounds:

Titanium carbide TiC aka titanium-khamrabaevite (cubic rock salt structure) Mohs 9-9.5 refractory
Vanadium carbide VC (vanadium is not too common) vanadium-khamrabaevite
similar is: NbC and TaC (Nb is not abundant, Ta is extremely rare)
Zirconium cabide ZrC [1] (same structure but no natural mineral present)
similar is: HfC (Hf is pretty rare)
Iron carbide (this here is not cementite!!) iron-khamrabaevite (unknown stability, likely very hard)

Chromium_carbide (various stoichiometric & structures - may point to useful covalent behavior)
Cr₃C₂ Tongbaite (refractory, Mohs 9.6; orthorhombic; 6.64g/ccm) Cr is not too abundant
Cr₂₃C₆
Molybdenium carbide (de) Mo₂C (insoluble, two modifications α and β) Mo is rather rare
Tungsten_carbide (hexagonal, Mohs 9) W is rather rare

copper and zinc are more electronegative => more covalent behavior => organometallic compounds

Boron carbide B₄C [2] (boron is not too common)
Aluminium carbide [3] (reacts with water - releases methane gas CH₄)
Beryllium carbide Be₂C (very hard but reactive, toxic and rare)
Magnesium carbide ??? - magnesium acetylide Mg₂C₃ (de wikipedia)
Calcium carbide CaC₂ (an acetylide - reacts with water - releases ethyne gas C₂H₂)
TODO: La, Ce, (Li, Na, K)

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 '''sp<sup>2</sup> allotropes:'''
+* Graphite (today single cystallinge graphite is called HOPG for highly ordered pyrolytic graphite) <br>Future: POPMG for "perfectly ordered piezomechanosynthesized graphite.
 * Buckyballs (convex curvature; concave from inside) – weak molecular solids
 * Nanotubes (no curvature – flat rolled)