ferreux

Ferreux is a French adjective and, less commonly, a noun form used in scientific and technical contexts to denote iron-containing or iron-related characteristics. It corresponds to the English term ferrous. The masculine singular is ferreux, with feminine ferreuse and plural forms depending on the noun they modify. The term is widely used in chemistry, metallurgy, and geology.

Etymology and scope

Ferreux derives from fer, the French word for iron, with the adjectival suffix -eux. In contrast to ferrique, which denotes iron in the +3 oxidation state, ferreux refers to iron in the +2 oxidation state in many chemical and mineralogical contexts.

Usage in science

In chemistry, ferreux indicates iron in the +2 oxidation state. For example, ferreux sulfate (ferrous sulfate, FeSO4) contains iron(II) ions. In mineralogy and geology, ferreux minerals or compounds are those in which iron is predominantly present as Fe2+; ferrique minerals contain iron mainly as Fe3+. This distinction helps categorize compounds and rocks by oxidation state and chemical behavior.

Related terms

A related term is ferrugineux, meaning iron-bearing or ferruginous, often used to describe rocks or soils with a noticeable iron content that can produce a rusty coloration. The terminology ferreux and ferrugineux are distinct but both concern iron-containing materials, whereas ferrique denotes iron in the +3 state.

See also

Ferrous and ferric, for cross-language equivalents and broader context in inorganic chemistry; ferrique and ferrugineux for related French terminology in geology and mineralogy.