Crystal structure of alite in monoclinic phase

The monoclinic phase of alite was investigated using transmission electron microscopy. The diffraction patterns were analyzed. The coordinates of all reflections could be expressed as ha*^rarr;+kb*^rarr; +lc*^rarr;±m(a*^rarr; /6+b*^rarr;/6+2c*^rarr;/6), where h, k and l are Miller indices, a*^rarr;, b*^rarr; and c*^rarr; are primitive vectors of the reciprocal lattice, m=0, 1, 2, or 3. The result indicates that the structure modulation in M* is a one-dimensional type with a structural modulation along the [112] direction. The modulated structure was exmined by a high-resolution transmission electron microscope image as wavy contrast streaking along the direction [112] with a sequence of six times the (112) spacing.