Straight molecules

When determining whether a molecule is polar or nonpolar, it is important to consider the geometry of the molecule. Carbon dioxide is nonpolar because it is a straight molecule in which the dipoles balance each other so that the center of negative charge coincides with the center of positive charge. Nonpolar CO can be contrasted... 

Straight molecules can pack together more densely and give crystals of higher melting point than the melting points of bent molecules of the same size in other words, more energy is required to separate the molecules when they are heated. 

The use of asbestos is being curbed because it has been shown to cause lung cancer if inhaled. A simple explanation for this is that the straight molecules in asbestos cleave easily. The asbestos dust consists of small sized fibrous particles... 

For example, for an ideal straight molecule both X2 and X3 are equal to zero and K = 1 for an ideal spherical molecule all three eigenvalues are equal to 1/3 and K = 0. For all planar molecules the third eigenvalue X3 is 0, there being no variance out of the molecular plane, and K ranges between 0.5 and 1, depending on the molecule linearity. 

The size and shape of molecules differ from compound to compound, and because of that, some of them have a nonuniform electrical charge distribution within the molecule. For example, carbon disulfide, CS, is a very symmetrical and straight molecule and is nonpolar whereas water is slightly bent and is polar. Ethanol is a linear molecule, but because of the oxygen at one end, it is also polar. In addition, attractions can occur between molecules by what are known as hydrogen bonds. Molecules that have O, N, and F atoms located near one end can readily form hydrogen bonds. Some of these possibilities are shown in Figure 3-2, p. 22. 

Acetylene. C2H2 99.9 51.2 24.3 24.3 61 axis of symmetry straight molecule... 

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