Electrical resistivity of graphite

Graphite anodes when used in soils are invariably placed in a carbonaceous backfill. This helps to compensate for the lower electrical resistivity of graphite when compared with silicon iron. In such an environment, no build-up of a film of high resistance between the anode and backfill occurs, unlike silicon-iron anodes where the resistance can increase with... 

The resistivity (a measure of electrical resistance) of graphite is (0.4 to 5.0) X 10-4 ohm-cm in the basal plane. (The basal plane is the plane of the six-membered rings of carbon atoms.) The resistivity is 0.2 to 1.0 ohm-cm along the axis perpendicular to the plane. The resistivity of diamond, 1014 to 1016 ohm-cm, is independent of direction. How can you account for this behavior in terms of the structures of graphite and diamond ... 

The four valence electrons of carbon are involved in three a bonds and one tt bond with its neighbors in plane. The electrical conductivity of graphite is due to TT bonded electrons. In contrast to insulator diamond, the electrical resistance of graphite along the basal plane direction is 4.1 X cm, a figure of the same... 

Other new tables include the Melting Curve of Mercury, Enthalpy of Hydration of Gases, and Electrical Resistivity of Graphite Materials. Several other tables have been updated with recently reported data. 

Figure 2.26 Relative change in the specific electrical resistivity of graphite Type MSY as a function of temperature. Source Reprinted from SGL Carbon Group technical literature, Carbon and Graphite Manufacture and Properties, 1995.

Electrically, graphite can be considered as a semi-metai, that is a conductor in the basal plane and an insulator normal to the basal plane. Its atomic structure is such that the highest-filled valence band overlaps the lowest-empty conduction band by approximately 36 meV and the delocalized fourth-valence electrons form a partially-filled conduction band between the basal planes where they can moved readily in a wave pattern as they respond to electric fields.P°l Consequently, the electrical resistivity of graphite parallel to the basal planes (ab directions) is low and the material is a relatively good conductor of electricity. 

Kuznetsov, V.L., Butenko, Yu. V., Chuviln, A.L., Romanenko, A.I., Okotrrub, A.V., 2001, Electrical resistivity of graphitized ultra-disperse diamond and onion-like carbon, Chem. Phys. Lett. 336, 397-404. 

Jilai Xue, Jun Zhu, and Yunxia Song, Electrical Resistance of Graphitic and Graphitized Cathode Materials at Elevated Temperatures, Light Metals, (2010), 829-834. 

Electrical Conductivity of Water, 5-72 Electrical Resistivity of Graphite Materials,... 

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