Space-filling models cyclohexane

FIGURE 3 14 (a) A ball and spoke model and (b) a space filling model of the boat confor mation of cyclohexane Torsional strain from eclipsed bonds and van der Waals strain involving the flagpole hydrogens (red) make the boat less stable than the chair... 

Figure 4.12 Representations of the chair conformation of cyclohexane (a) Carbon skeleton only (b) Carbon and hydrogen atoms (c) Line drawing (d) Space-filling model of cyclohexane. Notice that there are two types of hydrogen substituents—those that project obviously up or down (shown in red) and those that lie around the perimeter of the ring in more subtle up or down orientations (shown in black or gray). We shall discuss this further in Section 4.13.

Figure 4.14 (a) The boat conformation of cyclohexane is formed by "flipping" one end of the chair form up (or down). This flip requires only rotations about carbon-carbon single bonds, (b) Ball-and-stick model of the boat conformation, (c) A space-filling model. 

Figure 12-4 Extreme boat form of cyclohexane showing interfering and eclipsed hydrogens. Top, space-filling model center, ball-and-stick models bottom, sawhorse representations...

Figure 12-5 Chair form of cyclohexane showing equatorial and axial hydrogens. Top, space-filling model center, ball-and-stick model bottom, sawhorse representation. Notice that all the axial positions are equivalent and all the equatorial positions are equivalent. By this we mean that a substituent on any one of the six axial positions gives the same axial conformation, whereas a substituent on any one of the six equatorial positions gives the same equatorial conformation.

Table 5 shows four ways of representing the organic molecule cyclohexane. Each type of model used to represent an organic compound has both advantages and disadvantages. Each one highlights a different feature of the molecule, from the number and kinds of atoms in a chemical formula to the three-dimensional shape of the space-filling model. Keep in mind that a picture or model cannot fully convey the true three-dimensional shape of a molecule or show the motion within a molecule caused by the atoms constant vibration. 

Skeletal structures of cycloalkanes imply that there is empty space in the middle of the rings. Use SpartanView to look at. space filling models of cyclohexane, cyclodecane, and Qrclooctadecane. Which, if any, rings have empty space ... 

Molecular models (ball and stick models, space-filling models) which reproduce typical bond lengths and bond angels and hence stereochemical and congestional effects. However, certain aspects are not covered by the model they are, for instance, not soluble in cyclohexane in the same way as the original. 

Figure 15.6 Depicting cycloalkanes. Cycloalkanes are usually drawn as regular polygons. Each side is a C—C bond, and each corner represents a C atom with its required number of H atoms. The expanded formulas show each bond in the molecule. The ball-and-stick and space-filling models show that, except for cyclopropane, the rings are not planar. These conformations minimize electron repulsions between adjacent H atoms. Cyclohexane (D) is shown in its more stable chair conformation.

Figure 4-7 Conversion of the hypothetical planar cyclohexane into the boat form. In the boat form, the hydrogens on carbons 2, 3, 5, and 6 are eclipsed, thereby giving rise to torsional strain. The inside hydrogens on carbons 1 and 4 interfere with each other sterically in a transannular interaction. The space-filling size of these two hydrogens, reflecting the actual size of their respective electron clouds, is depicted in the ball-and-stick model on the right.

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