The phenomenon or condition of allotropy; the property of an element existing in multiple distinct physical or chemical forms.
From allotrope (a form of an element) plus -ism suffix (indicating a system or condition). The root comes from Greek 'allo-' (other) and 'tropos' (turning). The term developed in 19th-century chemistry alongside the discovery of elemental forms.
Allotropism explains why red phosphorus is safe to use on matchboxes while white phosphorus spontaneously ignites in air—same element, completely different danger levels depending on how the atoms are arranged.
Complete word intelligence in one call. Free tier — 50 lookups/day.