Réductrices

Réductrices, or reducing agents, are substances that donate electrons to other species in redox (oxidation–reduction) reactions. By doing so, they become oxidized while their partner is reduced. The strength of a reducing agent is often described by its standard reduction potential; more negative potentials generally indicate stronger reducing power under standard conditions. Reductants may act in aqueous or non-aqueous media and can be inorganic metals, gases, or organic compounds.

Common inorganic reductants include metals such as zinc, iron, and magnesium, which can reduce metal ions or oxides; hydrogen gas is also a widely used reductant. Carbon-based reductants such as carbon monoxide or carbon powder are employed in ore processing and synthesis. In organic chemistry, milder to moderate reductants include sodium borohydride (NaBH4) and lithium aluminum hydride (LiAlH4), while donor molecules like ascorbic acid function as biological or mild chemical reductants.

In biological systems, natural reductants such as NADH and NADPH supply electrons for biosynthetic pathways and detoxification processes. Reducing agents are essential in many laboratory techniques, such as hydrogenation, reductive amination, and the preparation of metal complexes. In industry, reducing conditions are used to extract metals from oxides, for example in smelting with carbon sources, and to selectively transform functional groups in organic synthesis.

Safety considerations include reactivity with oxidizers and potential air or moisture sensitivity. Handling and storage guidelines typically require appropriate containment, ventilation, and personal protective equipment, depending on the agent.