Krystallsystemer

Krystallsystemer, also known as crystal systems, are classifications of crystal structures based on their symmetry and lattice parameters. There are seven recognized crystal systems, each defined by specific combinations of lattice parameters and symmetry elements. These systems are used to categorize the vast array of crystal structures found in minerals and other materials. The seven crystal systems are:

1. Cubic: All lattice parameters are equal, and the angles between them are 90 degrees. This system includes structures like diamond and pyrite.

2. Hexagonal: Two lattice parameters are equal, and the angle between them is 120 degrees. The third parameter is perpendicular to the plane defined by the first two. Graphite is an example of a hexagonal crystal system.

3. Tetragonal: Two lattice parameters are equal, and the third is different. All angles are 90 degrees. Quartz is a common example of a tetragonal crystal system.

4. Orthorhombic: All lattice parameters are different, and all angles are 90 degrees. Galena is an example of an orthorhombic crystal system.

5. Monoclinic: Two lattice parameters are equal, and the third is different. The angles between the axes are 90 degrees, except for one angle which is not 90 degrees. Gypsum is an example of a monoclinic crystal system.

6. Triclinic: All lattice parameters are different, and all angles are different. Halite is an example of a triclinic crystal system.

7. Trigonal: This system is a subset of the hexagonal system, where the lattice parameters are equal, and the angles are 90 and 120 degrees. Calcite is an example of a trigonal crystal system.

Each crystal system is further divided into crystal classes, which describe the specific symmetry operations present in the crystal structure. The study of crystal systems is fundamental to crystallography, a branch of materials science that deals with the arrangement of atoms in solids.