12) water. The Columbia Encyclopedia, Sixth Edition. 2001 ...in the valence shell of oxygen to arrange themselves symmetrically at the vertices of a tetrahedron around the oxygen nucleus. The two pairs associated with covalent...
13) chemical bond. The Columbia Encyclopedia, Sixth Edition. 2001 ...molecules. If all four bonds are single, as in methane, the shape of the molecule is that of a tetrahedron. The importance of shared electron pairs was first realized...
14) isomer. The Columbia Encyclopedia, Sixth Edition. 2001 ...four different atoms or radicals bonded to it, arranged approximately at the corners of a tetrahedron centered on the carbon atom. For example, there are two optical...
