Formulaegység

Formulaegység is a Hungarian term that translates to "formula unit" in English. It is primarily used in chemistry to represent the smallest electrically neutral group of ions or atoms that forms a compound, particularly ionic compounds and covalent network solids. Unlike a molecule, which can exist independently, a formula unit represents the empirical ratio of the constituent ions or atoms in a crystal lattice or a larger structure.

For ionic compounds such as sodium chloride (NaCl), a formula unit represents the simplest ratio of sodium ions (Na+) and chloride ions (Cl-) that exist in the crystal structure. It does not imply that a single NaCl unit exists in isolation. Similarly, for covalent network solids like silicon dioxide (SiO2), the formula unit represents the empirical ratio of silicon and oxygen atoms, not a discrete molecule. The concept of a formula unit is crucial for calculating molar masses and determining stoichiometric relationships in chemical reactions involving these types of substances. It is a fundamental concept for understanding the composition and properties of many inorganic compounds.