Nine , isomers

Constitutional isomerism becomes more complex as the size of the hydrocarbon molecule is increased. For example, there are three constitutional isomers of pentane, C5H12. The number of constimtional isomers increases quite rapidly with an increasing number of carbon atoms. Thus, there are five constimtional isomers of hexane, CeH, nine isomers of heptane, C7H16, 75 isomers of decane, C10H22, and 366,319 isomers of eicosane, C20H42. You can begin to understand why it is possible to make so many different molecules based on carbon. 

Problem 1.25 Write Lewis structures for the nine isomers having the molecular formula C,H O, in which C, H, and O have their usual covalences name the functional group(s) present in each isomer. <... 

Problem 4.40 (a) Deduce structural formulas and give lUPAC names for the nine isomers of C,H,. (b) Why is 2-ethylpentane not among the nine ... 

FIGURE 7. The calculated structures of (a)-(d) four isomers of [Zn, N, C, H]+ ions and (e)-(m) nine isomers of [Zn, N, C2, H3]+ ions using the MNDO method with full optimization of geometry. Reproduced by permission of John Wiley Sons Ltd. from Reference 123... 

Nine isomers are described in Beil(Ref 1) and three are listed in Sax(Ref 2)... 

Draw structures and give IUPAC names for the nine isomers of C7H16. 

To sum up, derivatives of nine isomers of 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acids having the v-glycero-D-galacto (34),... 

In the fac configuration, also called the Pfeiffer-Schetty structure, nine isomers are possible four pairs of enantiomers and a centrosymmetric structure. Since the ligands are arranged parallel to one another, they sometimes are called sandwich complexes. The two mer and the nine fac orientations are depicted in [30],... 

A similar atom type partition is found for C76. This molecule has D2 synunetry and the expected 19-line spectrum is observed. The four upheld lines (5 < 137.1 ppm) are assigned to the 16 (4 x 4 atoms) graphitic carbons, whereas the remaining 60 carbons (15 x4 atoms, 5 > 141.3 ppm) make up the 12 five-membered rings. Some other higher fiillerenes have been successfidly characterized as mixtures of isomers. Thus for C78, five isomers are possible, but only three have been characterized by C NMR C2v (21 lines), C (21 lines), and D3 (13 lines). For Cg2, nine isomers are possible and three (possibly with traces of a fourth) have been seen, at least one C2 (41 lines), C2 (17 lines), and 3 (12 lines). For Cg4, 24 isomers are possible, but only two have been seen, D2 (21 lines) and D2d (10 lines). 

Draw Lewis structures for the nine isomers having molecular formula CsHgO, with all atoms having a zero formal charge. 

Give the structure and lUPAC name for each of the nine isomers having molecular formula C9H20 that contains seven carbons in the longest chain and two methyl groups as substituents. 

E7.15 Ignoring optical isomers, nine isomers are possible. Including optical isomers, 15 isomers are possible Read Section 7.10(a) Geometrical isomerism for a better understanding of all the possible isomers. 

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