It is very difficult to classify carbons as amorphous or purely crystalline, because you will find some degree of order (short range crystallinity) and disorder in most carbons. Raman spectroscopy is one of the best ways to rationalize the behaviour of carbons. Usually we see two peaks. The two peaks are called as D-band and G-band, and the ratio of the intensity quickly tell us the amount disordered carbon vs. graphitized carbon in any carbon. If we do Raman spectroscopy of carbon black we might see a higher intensity peak for the G band and a lower intensity of D band. This implies that carbon black has some graphitic character (hence conductive). Complete graphitization of carbon takes place under extreme conditions (> 2000 oC under inert atmosphere). A temperature range 600-900 oC is perhaps too low. 

Carbon black itself is nonconductive to my knowledge, however, graphitic carbon is conductive.

Dear Deepak Sridhar,

Sorry, but you are not correct in the terms you currently use. Both activated carbon and carbon black are not well-ordered, but not amorphous; they have low conductivities, but there is no reason to call them non-conductive. Please, see Chapter 2 - Carbon in Volume 1 of my book on UHTM available on my ResearchGate account.

Dear Igor,

maybe you are right regarding nonconductive, but in the abstract it is mentioned that beside others carbon (graphene/graphite) C is considered, i.e. materials with the typical sheet structure.

@Titus Sobisch  Dr. Sobisch. Sorry, I should have framed my question with Conductive C black  instead. These are often used as a conductive additive to rubber reinforcement, supercapacitor electrodes etc. For ex, 

http://www.cabotcorp.com/solutions/products-plus/carbon-blacks-for-elastomer-reinforcement/conductive

So why is this conductive?

Thanks

@Igor L Shabalin  Dr. Shabalin, I went through your book, and I understood that activated carbon is nanoporous assemblies of defective graphene and Cblack is partly crystallised OR AMORPHOUS spherical particulates?! So they would have mixture of SP2 and SP3? How will the C assembly look like in AC and C black?

Also, is conductive black different than just C black?

It is very difficult to classify carbons as amorphous or purely crystalline, because you will find some degree of order (short range crystallinity) and disorder in most carbons. Raman spectroscopy is one of the best ways to rationalize the behaviour of carbons. Usually we see two peaks. The two peaks are called as D-band and G-band, and the ratio of the intensity quickly tell us the amount disordered carbon vs. graphitized carbon in any carbon. If we do Raman spectroscopy of carbon black we might see a higher intensity peak for the G band and a lower intensity of D band. This implies that carbon black has some graphitic character (hence conductive). Complete graphitization of carbon takes place under extreme conditions (> 2000 oC under inert atmosphere). A temperature range 600-900 oC is perhaps too low. 

@M. Farooq Wahab. Hi Farooq, perfect! I see this problem in the same manner. When you look into AC Raman, you will still have G band, which is again depicting som conductivity. But this conductivity is less than CBlack conductivity.

So, to classify Carbon allotrope as crystalline, should the D peak intensity be high (No inplane vibration?- I am not a physicist, so might be sounding funny?)? Please explain

Thanks

Deepak, As far as I know the D and G bands are present in graphitic materials. The ratio of intensity of G/D often gives good clue about the nature of graphitization. However, it is not an absolute way to assign crystal structure. If we look at the Raman spectra of two extremes e.g. pure diamond and pure graphite, we know that both of them can exist as crystals. Diamond is perfectly crystalline yet it has neither D band nor G band. It has its own pure vibrational mode. See the note by Thermo "Characterizing Carbon Materials with Raman Spectroscopy" Joe Hodkiewicz.

Dear Deepak Sridhar,

 it not the magnitude of conductivity, to my knowledge, the major difference for their implementation (in most applications), but the magnitude of (active) surface as well as their important difference in (meso, nano-scopic level) mechanical properties.

Titus Sobisch: Please see https://www.researchgate.net/publication/267331006_Carbon_GrapheneGraphite

Chapter Carbon (Graphene/Graphite)

Dear Dr. Samaras,

How is the mechanical property aiding conductivity? 

regards

Dear Deepak Sridhar,  [Q: "How is the mechanical property aiding conductivity? "]

the magnitude of (active) surface is obvious, about why conductivity is aided, by the definition of conductivity. The mechanical property may be less obvious. However, if you consider the advantages of an elastic filler in applications (dental etc.) then you will draw a concept-picture. On the contrary, a non elastic filler is loosing "bonds" between neighbor clusters, that is sometimes critical [see PS] upon high volume changes due a driving force stress (electric, chemical, temperature, magnetic  etc.). Also, in composite "ceramic" electrodes (as one of the examples) some add Polytetrafluoroethylene (PTFE, i.e. teflon) powder to enhance elasticity, further.

PS:

1.  wikipedia:  https://en.wikipedia.org/wiki/Critical_exponent,  https://en.wikipedia.org/wiki/Lattice_graph

2. Diffusion and Reactions in Fractals and Disordered Systems [http://havlin.biu.ac.il/Shlomo%20Havlin%20books_d_r.php]

Dear Deepak Sridhar,

As an author of reference book I cannot ignore the opinions or terms used by the earlier authors of original/initial publications/references. That is why I wrote "...or amorphous..." there... However, I believe that the term "amorphous" is not appropriate to describe the structure of "sigma-sp2

Hi Deepak,

I'm trying to measure the conductivity and the resistance of both materials (AC and CB) in the laboratory. Could you please tell me the values that you have and the source?

Thanks a lot.

Best regards,

Juan