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Incoming links: X-ray crystallography
Laue X-ray diffraction experiment of 1912 2026-10-18
Max von Laue proposed crystal X-ray diffraction and wrote the theoretical section; Walther Friedrich and Paul Knipping performed the experiments.[ref]
Interferenz-Erscheinungen bei Röntgenstrahlen by Walther Friedrich, Paul Knipping and Max von Laue. pp. 303–304, 311: section authorship
An X-ray tube, lead apertures and shielding supplied a narrow beam through a crystal on a goniometer. Photographic plates recorded the direct beam and separate spots. Copper(II) sulfate trials preceded oriented zinc blende. Optical alignment was checked with X-rays. Removing the crystal removed the extra spots; grinding destroyed their ordered arrangement; translation preserved it, while tilt changed it. Rotation about the beam rotated the pattern.[ref]
Interferenz-Erscheinungen bei Röntgenstrahlen by Walther Friedrich, Paul Knipping and Max von Laue. pp. 311–318: apparatus and controls
Spots and orientation dependence supported wave interference and three-dimensional crystal periodicity. They determined neither all atomic positions nor an absolute wavelength scale. The authors left open whether the selected radiation originated as crystal fluorescence or was already in the incident beam. This differs from the modern Laue method.[ref]
Interferenz-Erscheinungen bei Röntgenstrahlen by Walther Friedrich, Paul Knipping and Max von Laue. pp. 310–311, 320–322: inference and spectral uncertainty
The 1914 Nobel Prize in Physics went to Max von Laue; the discovery's experimental account remains jointly credited to Walther Friedrich and Paul Knipping.[ref]
The Nobel Prize in Physics 1914 by Nobel Prize Outreach. 1914 award and laureate
The subsequent inference of particular crystal structures is developed under X-ray crystallography. X-ray crystallography 2026-10-18
X-ray crystallography infers a crystal structure from measured X-ray diffraction. Peak positions constrain the lattice geometry, while intensities constrain the atomic basis of a crystal; the inference also needs an experimental model and does not directly observe every atomic position.
X-ray diffraction 2026-10-18
X-ray diffraction is the angular redistribution of X-ray wave intensity through wave interference between scattered waves. In a crystal structure, repeated lattice translations select discrete outgoing directions by the Laue equations. A photographic plate can therefore turn invisible atomic periodicity into a visible constellation of spots. Their geometry constrains the Bravais lattice and its orientation; their wave intensities also depend on the crystal basis structure factor. Determining atomic positions belongs to X-ray crystallography and requires more information than recognizing a spot pattern.
The Laue X-ray diffraction experiment of 1912 established this phenomenon experimentally. The Laue method uses a fixed crystal structure with a range of incident wavelengths; the Bragg crystal reflection experiment of 1913 instead measured angularly resolved signals with a moving detector. These are different ways of finding the same coherent elastic scattering directions.