NHC molecules and phosphine ligands have been shown to stabilize radicals of this element. Bonding in compounds characterized by this element can be calculated through the styx rule. (10[1])An organic (10[2])compound (10[1])of this element is often drawn with its bridged bicyclic rings represented by a banana. (10[11]-5[2])The prefixes (10[6])closo-, (10[4])hypho-, (10[1])nido-, (10[1])and arachno- (10[2])are used (10[1])to name cluster compounds containing (-5[1])hydrogen and this element, (-5[1])per Wade’s rules. (10[1])This (10[1])element (10[1])tends (10[1])to form three-center, two-electron (10[1])bonds, (10[1])leading it to often (10[1])be called “electron deficient.” (10[3]-5[1])Like beryllium (10[1])and aluminum, (10[2])this element (10[1])can form (10[2])three bonds (10[3])with no lone (10[1])pair, (10[1])violating (10[1])the octet (10[1])rule. (10[2])A hydride (10[2])of this element is used as a reducing (10[1])agent. (10[1])For 10 points, name this element with (-5[1])atomic number 5. (10[1])■END■ (10[17])