# Why does CO2 accept electrons?

CO2 is a lewis acid as it can accept electrons. But as the octets of all atoms of CO2 are complete why does it accept electrons? Shouldn't it donate electrons and be a lewis base?

• Most of the stable compounds have complete octets on all atoms. This has nothing to do with their willingness to donate or accept electrons. – Ivan Neretin May 1 '16 at 15:31
• @IvanNeretin Then how do we determine it? – user456 May 1 '16 at 15:33

$\hspace{7.5cm}$
This makes the central carbon electrophilic, and explains the reactivity of the carbonyl moiety towards nucleophiles. Similarly, $\ce{CO2}$ undergoes addition reactions with Grignard reagents to form carboxylate anions.
$\hspace{4cm}$