To solve the problem, we need to explain why is strongly reducing while is strongly oxidizing.
1. Analyze as a Reducing Agent:
A species is reducing if it easily loses electrons (is oxidized). has the electronic configuration . When oxidized to , it becomes , which is a half-filled configuration in octahedral complexes, highly stable due to exchange energy and symmetry. The standard reduction potential is negative, indicating is favorable, making a strong reducing agent.
2. Analyze as an Oxidizing Agent:
A species is oxidizing if it easily gains electrons (is reduced). has the configuration . When reduced to , it becomes , a half-filled configuration, which is very stable. The standard reduction potential is highly positive, indicating is favorable, making a strong oxidizing agent.
Final Answer:
is strongly reducing because it oxidizes to the stable ( , half-filled ), with a negative reduction potential ( ). is strongly oxidizing because it reduces to the stable ( , half-filled), with a high positive reduction potential ( ).