Water-soluble complexes of nickel in this oxidation state can be prepared with TPPTS. Gold atoms with this oxidation state are attached to cyclic alkyl amino carbenes in complexes isolated by Guy Bertrand’s lab. A form of iron in this oxidation state is used to construct permeable reaction barriers used for groundwater remediation. Nickel in this oxidation state is often sourced from a complex in which it is attached to two (*) 1,5-cyclo·octa·dienes. Before the oxidative addition step, this is the oxidation state of palladium in the catalyst of the Heck reaction and most other palladium-catalyzed cross-couplings. A half-reaction that produces an element in this oxidation state has the lowest standard reduction potential on the electrochemical series. This is the oxidation state of iron at the center of iron pentacarbonyl. For 10 points, what number is the oxidation state of any pure element? ■END■
ANSWER: +0 [or plus zero]
<Geoffrey Chen, Chemistry>
= Average correct buzz position