Linear Electronic Geometry AB2 Species No Lone Pairs on A

8-5 Linear Electronic Geometry AB2 Species (No Lone Pairs on A) 

Several linear molecules consist of a central atom plus two atoms of another element, abbreviated as AB2. These compounds include BeCl2, BeBt2, and Bel2 (in their gaseous state), as well as CdX2 and HgX2, where X = Cl, Br, or I. All of these are known to be linear (bond angle = 180°), nonpolar, covalent compounds. 

Let s focus on gaseotis BeCl2 molecules. We wrote the Lewis formula for BeCl2 in Example 7-4. It shows two single covalent bonds, with Be and Cl each contributing one electron to each bond. 

In many of its compounds. Be does not satisfy the octet rule (see Section 7-8). 

Another linear, nonpolar AB2 molecule is carbon dioxide, CO2. 

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