Interactive course of Crystallography
This course introduces the basic concepts of crystallography and is freely available on the web for everyone. The symmetry of crystalline material and the properties of diffraction are presented by means of interactive applets. The description of structures is greatly facilitated by the combination of drawing tools and easy access to databases.
specifically, the following applets are available :
Due to new security issues with recent versions of java, the applets might not be able to start by clicking on it. In case of difficulties, press the download button (either on the top or bottom of page) and click on the downloaded .jar file to start the applet.
For Mac OSX be sure to remove the file "JavaAppletPlugin.plugin" in your system and install the Apple version of java (currently version 6)
- Bragg scattering
A Flash animation to illustrate constructive interferences as expressed by Bragg's law
An applet to transform a unit cell ant its content to another cell. Based on the originial CIF file, the applet generates a new CIF file resulting from the transformation specified by the user.
- Charge flipping
An applet to solve the phase problem in diffraction by the charge flipping algorithm. The user can create a 2D crystalline structure and follow the evolution of the algorithm in solving the structure.
- Crystal symmetry
An applet to represent (among others) the general and special positions of the 230 space groups.
An applet to represent any type of crystalline structure given the lattice parameters, the space group and the atomic coordinates of symmetry independent atoms. It is also possible to import directly a structure from the ICSD database or from a CIF file.
- Diffraction and
An applet to calculate the Fourrier Transform of a density function ρ(x) yielding the complex magnitude G(S). The applet is also able to calculate the inverse Fourier transform of G(S). The density function can be either periodic or non-periodic. Numerous tools can be applied in order to understand the role of amplitudes and phases which are of particular importance in diffraction phenomena.
An applet to simulate any type of diffraction pattern based on the Ewald sphere and the reciprocal lattice. In particular, Laue patterns, Debye Scherrer diagrams, rotating crystals and even precession photographs can be generated.
- Escher Web
An applet to simulate any symmetry decoration of the plane (17 two-dimensional planar groups).
Mpeg: 5.1 MB - 2.8 MB
QuickTime: 4.7 MB - 2.3 MB
Video sequence illustrating the diffraction phenomenon based on the Ewald sphere.
to the discovery of symmetry
An applet to discover the point group symmetry of platonic and other polyhedra. In particular, rotations, inversion and combinations of them can be simulated.
diffraction files (For license
reason, this applet is only available at the EPFL
An applet to extract the powder diffraction patterns from a database. Each pattern can be retrieved by specifying some characteristics, e.g. its element contents and number, the name of the compound, the pdf number of the compound or the d-values of the most intensive lines.
From a periodic diagram generated by EWS, the user is guided step by step by the applet in order to create the reciprocal lattice corresponding to the periodicity of the initial periodic pattern.
An applet to simulate the X-ray diffraction intensities for single crystal in reciprocal space and powder diffraction patterns. Structures can be selected from the ICSD database or from CIF files.
The website of the International Union of crystallography (IUCr) maintains a list of public resources dedicated to crystallography education available at this link.