krystallisk

Krystallisk is a term used in Norwegian and Swedish to describe anything relating to a crystal or composed of crystals. In science, krystallisk describes a solid with a highly ordered, repeating arrangement of atoms, ions, or molecules extending in three dimensions, known as a crystal lattice. The term derives from the Greek krystallon (crystal) via Latin and Germanic languages, and is used in mineralogy, chemistry, physics, and materials science.

Key features include long-range order, defined crystallographic directions, and characteristic external shapes. Substances with crystalline order have a well-defined melting point and often exhibit anisotropic properties; their structure can be described by a unit cell and Bravais lattice, giving rise to the seven crystal systems (cubic, tetragonal, orthorhombic, etc.). In contrast, amorphous solids lack long-range order and display gradual glass transitions rather than a sharp melting point.

Formation and testing: Crystallization occurs via nucleation and growth from a solution, melt, or gas. Conditions such as temperature, concentration, impurity levels, and solvent interactions influence crystal size, shape (habit), and polymorphism, where the same compound forms different crystal structures. X-ray diffraction is a primary method to determine crystal structure; diffraction patterns reveal lattice spacings via Bragg's law, and electron microscopy can visualize lattice fringes.

Examples and applications: Common crystalline substances include table salt (NaCl), quartz (SiO2), and metals with face-centered cubic, body-centered cubic, or hexagonal close-packed lattices. Crystallinity affects optical clarity, hardness, and electrical or thermal conductivity, making crystalline materials central to electronics, optics, pharmaceuticals, and construction.