Distinction between space groups having principal rotation and screw axes, which are combined with twofold rotation axes, using the coherent convergent-beam electron diffraction method

23 sets of space groups remain indistinguishable by the convergent-beam electron diffraction (CBED) method. Recently, Tsuda, Saitoh, Terauchi, Tanaka & Goodman [Acta Cryst. (2000), A56, 359-369] demonstrated that the coherent CBED method can distinguish two space-group pairs (I23, I2₁3) and (I222, I2₁2₁2₁) by observing the relative arrangements of 2-fold-rotation and 2₁-screw axes. The other ten space-group sets, which are composed of principal rotation and screw axes and other 2-fold-rotation axes such as P321 and P3₁21 (P3₂21), are shown to be distinguishable using the coherent CBED method.