This website provides a means to convert fractional crystallographic coordinates to orthogonal Cartesian coordinates and vice versa.

Help is available in the tooltips which appear when you hover the mouse over elements in the mid-bar.

Fractional coordinates are orthogonalised using the PDB convention for aligning orthonormal axes with the unit cell vectors i.e. the X-axis is parallel with a, the vector b lies in the XY plane and Z is parallel with the reciprocal lattice vector c*. This is described in more detail here.

Chemical X-ray structures are usually stored as fractional coordinates in Crystallographic Information File (or CIF) format whereas macromolecular structures are stored as orthogonal Ångstrom (Å) coordinates in Protein Data Bank (PDB) files. CIF's can be converted to PDB format automatically using this website, which is also by the same author!

This website was put together by jbcooper_at_fastmail_dot_net and use of it, or the code which can be obtained here, comes with no warrantees, etc.

It is written in Lua and uses the lua-matrix library.

Corrections and suggestions for improvement are gratefully received and please let me know if you find any bugs!