Chlorine_dioxide.png new as SVG and with angle/bondlength. Note: This is more or less the structure given by Pauling on page 264 of his <i>General Chemisty</i>, although he puts three dots between the left-hand oxygen and the chlorine, as well as a line segment, instead of two line segments and a dot on the chlorine as we have here. But the <a rel="nofollow" class="external text" href="http://authors.library.caltech.edu/9165/1/BROpnas33b.pdf">1933 paper by Brockway</a> differs from this in having a single bond going to the other oxygen, and three lone pairs on that oxygen. That makes more sense, as it puts only nine electrons around the chlorine, rather than eleven in Pauling's diagram or in this diagram. Actually, Brocksay (who collaborated with Pauling) means his diagram to represent a mixture of a Lewis electronic structure with one lone pair and a lone electron on the chlorine, and three lone pairs on the left-hand oxygen, and a structure with two lone pairs on the chlorine and two lone pairs and a lone electron on that oxygen. Each of these two structures also has a single bond going to each oxygen. In these structures, each atom is surrounded by seven or eight electrons. Brockway says that the three-electron bond is equivalent to half a single bond. This gives a total of two and a half single bonds in the molecule, not two double bonds or a double bond plus one and a half single bonds as in this diagram. Of course, Brockway mentions that in reality we have a resonance between the structure with the three-electron bond going to one oxygen and the structure with it going to the other oxygen.
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