Molecular structure trigonal planar arrangement

To determine the molecular structure, we must count the electron pairs around the sulfur atom. In each resonance structure the sulfur has one lone pair, one pair in a single bond, and one double bond. Counting the double bond as one pair yields three effective pairs around the sulfur. According to Table 13.8, a trigonal planar arrangement is required, yielding a V-shaped molecule ... 

A9.35 The structure is built up of linear NO groups arranged end-to-end parallel to c, and trigonal planar NO groups stacked in a staggered fashion normal to the c-axis. The central N atoms of the two molecular ions are arranged in the same way as the C atoms in graphite. 

Hgure 19-i 6 molecular structure of formic acid is planar, with a roughly equilateral trigonal arrangement about the carbonyl carbon. 

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