The accurate determination of cell dimensions from single-crystal X-ray photographs

The accurate determination of cell dimensions by a graphical extrapolation method from single-crystal X-ray photographs has been discussed by Farquhar & Lipson and applied by them to an orthorhombic crystal, thallium hydrogen tartrate. In the present paper an alternative method of lower accuracy but greater simplicity is described. An account is also given of the application of extrapolation methods, both graphical and analytical, to the determination of the cell dimensions of a monoclinic crystal, a heat-treated orthoclase felspar. Procedures for determining accurate cell dimensions of orthorhombic, monoclinic and triclinic crystals are outlined.