ionlattice

An ionic lattice is a three-dimensional, periodic arrangement of ions in a solid formed by electrostatic forces between positively charged cations and negatively charged anions. In such lattices, ions occupy regular lattice points, producing well-defined crystal structures and high lattice energies.

The structure is often described as a Bravais lattice with a basis of ions. Common ionic lattices include the rock-salt structure (NaCl), in which each ion is sixfold coordinated; the CsCl structure, with eightfold coordination; and the fluorite structure (CaF2), in which Ca2+ forms a face-centered cubic lattice with F− occupying tetrahedral sites. Other examples include zinc blende (ZnS) and perovskite-derived ABX3 structures. The specific arrangement influences coordination numbers, bond lengths, and diffusion pathways.

Lattice energy, the energy released when gaseous ions form the lattice, depends on the charges, their sizes, and the geometry. It is described by models such as the Born-Lande equation and the Madelung constant, and it helps explain the high melting points of ionic compounds.

In solids, ionic lattices are typically brittle and electrically insulating. Ionic conduction is minimal in a perfect crystal but becomes significant when the lattice is molten or contains defects or dopants, enabling ion mobility. Solid-state ionic conductors are important in batteries and electrochemical devices.

Characterization commonly uses X-ray or neutron diffraction to determine lattice parameters and defect populations. Synthesis methods include high-temperature solid-state reactions and precipitation from solution. Defects such as Schottky and Frenkel defects influence diffusion and stability.