Carbon in the core

There may also be a significant amount of carbon in the core, with values of up to 4% possible, although this depends upon the amount available in the early Earth (Wood, 1993 Halliday and Porcelli, 2001). The amount of carbon that is supplied across the core-mantle boundary into the mantle is not known. 

The presence of a carbon in the core of the ring indicates that these macrocycles will form organometallic interactions upon metal binding. In biological systems, naturally occurring organometallic complexes are rare. The cobalamin cofactor is one of the more important examples, which possesses an axial metal-carbon bond in a cobalt porphyrinoid macrocycle (77). Another common example is seen in carbon-monoxide deactivated ferrous heme (22) ... 

Each core investigated was surrounded by a blanket at least 12 inches thick which consisted of 83.32 U-238 and 7.32 stainless steel. The assumed density of carbon in the core was 2.25. The fission ratios and reactivity coefficients for die first case listed in the table were determined at the center of a core having the same composition as listed, but with a low density inner blanket. 

The difference in the core-core energy for AMI and MNDOfor carbon-hydrogen and oxygen-hydrogen eractums. 

Holden et al. [27] reported the first Raman results on nanotubes produced from a Co-catalyzed carbon arc. Thread-like material removed from the chamber was encapsulated in a Pyrex ampoule in -500 Torr of He gas for Raman scattering measurements. Sharp first-order lines were observed at 1566 and 1592 cm and second-order lines al 2681 and 3180 cm , but only when cobalt was present in the core of the anode. These sharp lines had not been observed previously in... 

In an effort to better understand the differences observed upon substitution in carvone possible changes in valence electron density produced by inductive effects, and so on, were investigated [38, 52]. A particularly pertinent way to probe for this in the case of core ionizations is by examining shifts in the core electron-binding energies (CEBEs). These respond directly to increase or decrease in valence electron density at the relevant site. The CEBEs were therefore calculated for the C=0 C 1 orbital, and also the asymmetric carbon atom, using Chong s AEa s method [75-77] with a relativistic correction [78]. 

J. Chen, L. Yang, H. Yang, J. Dong, Electronic and transport properties of a carbon-atom chain in the core of semiconducting carbon nanotubes, Phys. Lett. A, vol. 316, pp. 101-106, 2003. 

The soccer ball shaped framework of Cgg was confirmed for the first time by the X-ray crystal structure of 13 [52]. The bridging of the OSO4 unit occurs in the characteristic 1,2-mode to a [6,6] double bond of the fullerene core. The 17 sets of carbons in the C2v-symmetric 13 were assigned using the 2D NMR INADEQUATE technique on the basis of their connectivities [53]. In these experiments C-enriched material was used. The coupling constants fall into three categories, 48, 54—57 and 65-71 Hz. These values can be attributed to the three types of C-C bonds present in 13, namely C(sp )-C(sp ), the longer [5,6], and the shorter [6,6] bonds, respectively [53]. 

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