Krystallografien

Krystallografien (crystallography) is the scientific study of the arrangement of atoms in crystalline materials. It investigates how atoms are ordered in a periodic lattice, the geometry of the repeating unit (the unit cell), and the symmetry described by space groups. The central aim is to determine three-dimensional atomic structures from diffraction data and to relate structure to properties of materials.

The primary technique is X-ray crystallography. A crystal diffracts X-rays into a pattern that encodes the electron density. Using Bragg’s law and Fourier methods, scientists reconstruct an electron-density map and build an atomic model. Successful work depends on obtaining suitable crystals, collecting high-quality data, solving the phase problem, and refining the model. Other methods include neutron diffraction, which highlights light elements and magnetic ordering, and electron diffraction (electron crystallography), used for very small crystals and nanomaterials. Powder diffraction analyzes polycrystalline samples.

Historically, diffraction by crystals was demonstrated by Laue in 1912, and Bragg and Bragg formulated the Bragg law. X-ray crystallography enabled the determination of the DNA double helix in 1953 and has since become essential to chemistry, biochemistry, and materials science, including pharmaceuticals and mineralogy.

Today, crystallography uses advanced light sources such as synchrotrons, cryo-cooling to preserve native states, and computational methods to solve large macromolecular structures. The field continues to evolve with new methods and applications in structure-guided design and materials engineering.