Isomer space filling structure

The structural isomers of C4Hio- Each molecule Is represented in three ways a ball-and-stick structure, a space-filling structure, and a structure that shows the shared electrons as lines (a Lewis structure), (top) Normal butane (abbreviated n-butane). (bottom) The branched isomer of butane (called isobutane). 

A structural model is a three-dimensional representation of the structure of a compound. There are two kinds of structural models ball-and-stick models and space-filling models. Figure 13.6 shows ball-and-stick models for the five isomers of C6Hi4. Notice that they show how the carbon and hydrogen atoms are bonded within the structures. 

Draw two isomers of 3-hexene in line notation, one with two ethyl groups on the same side of the C=C unit and one with the two ethyl groups on opposite sides of the C=C unit. Use a molecular modeling program or a model kit to show both structures as space-filling models. 

Fig. 12.7 Structures of the cis- and trans-isomers of (a) the hexapyrrolic calix[4]pyrroles 9a and 9b reported by Anzenbacher and coworkers, [24] (b) the dieacyl calix[4]pyrroles cis- and trans-isomers 10a and 10b, and (c) the space filling model DFT-optimized structures of the complexes [10a H2PO4]" and [10b H2PO4] reported by Panda and eoworkers [26]. (Reprinted from Org. Biomol. Chem. 2014,12, 278-285, with the permission fiom the Royal Soeiety of Chemistry)...

Fig. 10.7 Structures of the new Dawson-like WjgX POM type, the Wig cages are shown as sticks and the central XO group is represented as space filling model. Left Y -[Wig056(X06)] ° X = W and Te. Right P -[Wig056(I05)] being the first example of p isomer...

Stereoisomers that result from restricted rotation around single bonds are atropisomers. (5)-l,l -binaphthyl is an example of an atropisomer. The space-filling model is identical to the ball-and-stick model, but it shows the three-dimensional structure more clearly. The naphthyl groups cannot rotate around each other. Therefore, two nonsuperimpos-able, mirror-image isomers exist. 

However, in 1869 the Zurich chemist Johannes Wislicenus synthesized a new compound, a third distinct isomer of lactic acid, and showed that it had to have the constitution that had hypothetically been imputed to "meat" lactic acid. According to a secondhand report, Wislicenus inferred that "meat" lactic therefore had to have exactly the same constitution as that which had already firmly been established for "milk" lactic. The two distinct lactic acids derived respectively from meat and from milk were thus henceforth known as what were called "absolute" isomers—that is, isomers that possessed exactly the same structures, as far as one could tell, the source of whose isomerism therefore remaining mysterious. Wislicenus concluded that the isomerism must somehow be explained by "the different arrangements of their atoms in space." For instance, perhaps density measurements would show that the arrangements of the atoms of the different isomers fill space more or less efficiently, even though the formulas are identical. ... 

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