ᅟThe term speciation is used for over 30 years, with different meanings. In the early 2000s, a reference definition was proposed. The elemental distribution is discussed only with respect to molecular structures. Polytatomic entities such as amorphous or crystalline structures, dispersed in a liquid or gas, or in the solid phase, are not taken into account. The distribution of the element, both at the interfaces and in the solids, is not yet considered. This editorial discusses the limitations of this definition and its consequences. The different terminologies proposed from the reference definition are also discussed. Given all these considerations, it is proposed that speciation is considered as a description of the physical and chemical characteristics of an element. This description should be given from the atomic scale of this element to the scale of the surrounding medium, in the continuum of size, from the dissolved or gaseous phase to the solid phases.
Keywords: Fractionation; Interface; Nanoparticle; Physicochemical description; Solid phase.