ioonühend

An ioonühend, or ionic compound, is a chemical compound composed of ions held together by electrostatic forces. These forces are the attraction between positively charged ions (cations) and negatively charged ions (anions). Ionic compounds are typically formed between metals, which tend to lose electrons to become cations, and nonmetals, which tend to gain electrons to become anions. The formation of an ionic bond involves a complete transfer of electrons from one atom to another, resulting in the creation of these charged species.

The characteristic properties of ionic compounds arise from the strong electrostatic attraction between the ions. They generally exist as crystalline solids at room temperature with high melting and boiling points. This is because a significant amount of energy is required to overcome the strong ionic bonds holding the crystal lattice together. In the solid state, ionic compounds do not conduct electricity because the ions are fixed in their positions. However, when melted or dissolved in water, the ions become mobile and can carry an electric current, making molten or aqueous solutions of ionic compounds good electrical conductors. Ionic compounds are often soluble in polar solvents like water, as the polar solvent molecules can surround and separate the ions, a process known as solvation. They are typically insoluble in nonpolar solvents. The empirical formula of an ionic compound represents the simplest whole-number ratio of ions in the compound.