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Some information on SCHAKAL 99

SCHAKAL 99 is a computer program for the graphic representation of molecular and solid-state structure models. A first version of this program has been written in 1979 on a Sperry-UNIVAC computer (E. Keller, Chemie in unserer Zeit 14 (1980), 56-60).The most important features of this program are specified in the following. (! = new, + = improved [as compared to SCHAKAL 97])

Model types

  • Wire model
  • Ball-and-stick model; space-filling model
  • Intersection trace between space filling model and plane
  • Intact unique molecules or packing diagrams (with or without H bonds) from crystallographic data
  • Box-like or polyhedrally shaped models from cryst. data
  • Spherical or (hkl) surface models from cryst. data
  • Automatic generation of bonds and specific drawing parameters for the individual types of atoms

Display styles

  • Outlines; Hatching by parallels, meridians, or grids
  • Shading by randomly or regularly dithered dots; "realistic" multi-colour shading with shadows and highlights
  • Pseudo-"Cloud" representation (simple) of atoms/bonds
  • Optional perspective projections
  • Optional stereo drawings with stereo shading/labelling.
  • Optionally depth-dependent line thickness, darkness, and/or pseudo-transparency.
  • Fourier backgrounds


  • !+ On-screen rotations including zoom and pan functions for wire, ball-and-stick and space-filling models.
  • Alignment of a least-squares plane/line or of crystallographic vectors (mostly not on-screen !).
  • Optional rotations (or translations) of parts of the model, e.g., rotation of substituents about bonds (not on-screen).


  • Facility to label atoms automatically with "names", element symbols, or coordinates (simple line-style characters, but with adjustable size, boldness, and slantedness).
  • Label positions are optimized for minimal overlap. Labels may be positioned inside and/or outside the atom circles.
  • Facility to modify label positions via the mouse.


Facility to get information on ...

  • Atoms and bonds
  • Model statistics
  • distances, angles, and torsion angles
  • steric trouble
  • Current switch and parameter settings
  • view direction

Structure data Input

  • Cell parameters; atom names and coordinates
  • Space group symbol (conventional or non-conventional) or single symmetry operations
  • Input defining a parallelepipedal or polyhedral section of a crystal structure or a (hkl) "surface model".
  • + Optional translation of SHELX, CSD, ICSD, PDB, and CIF data

Program control

  • + "Home-made" GUI (see image below). The GUI generates ...
  • Simple commands which allow to select individual (or various groups of) atoms/bonds.
  • Facility to select atoms or bonds by the mouse or by means of an irregular polygon drawn around them.
  • Various "distributed command files" for routine tasks
  • Facility to generate command files by recording user input.
  • Facility to edit structural data and command files "on-line"
  • Detailed on-line help functions;
  • Interactive manual surfable with the mouse (no Hypertext !)

Graphical Output devices

  • 256 colours or black-white [B/W] screen drawings
  • TIFF/.pcx file with up to 4 x the (linear) screen resolution
  • 6-8 colours or B/W HP-GL file (for HP plotter or text proc.)
  • B/W HP LaserJet 3 - 6 (or fully compatible), 150 - 600 dpi
  • 256 colours or B/W HP-GL/2 file (for certain HP printers)
  • 256 colours or B/W Postscript/EPS
  • 256 colours or B/W Windows Metafile (very large files)
  • 256 colours or B/W Windows printer (only under MS-Win)


  • MS-Win version (A version) (Win9x/ME/NT/2K/XP). Capacity: 40000 atoms and bonds. The Win version is significantly less easy to use than other Win applications (due to the different GUI, see image below).
  • UNIX/X-Windows version (B version). Capacity: 40000 atoms/bonds. The UNIX version is known to run under ...
    Irix 5.3 to 6.5; Solaris 2.5.1; Dec-OSF1 (DEC Alpha); Aix 3.5/4.2; HP-UX 9/10; Linux.

Extent of supply

SCHAKAL 99 consists of the following items:

  • the executable programs (MS-Windows version only)
  • the FORTRAN / C source code of about 45000 lines (UNIX version only); FORTRAN 77 and ANSI C compiler required.
  • an interactive hierarchical on-line manual in English (about 330 pages, if printed); note: a Tutorial Manual may be donwloaded from the DOWNLOAD section of this site (see bottom).
  • a program to make a printout of this manual
  • a space group database; some data set examples
  • a number of "distributed command files" for routine tasks
  • installation program and makefile (UNIX versions)


The image shows the SCHAKAL 99 window (this one generated under MS Windows NT) containing the graphical user interface (GUI) and the drawing area. The GUI is mouse-driven but allows input from the keyboard as well.

The GUI does not conform to the MS-Windows or OSF-Motif standards, i.e., it is less flexible, less intelligent and less easy to control than the GUI of the average contemporary program.

The program may be downloaded from the DOWNLOAD section.

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