Glide direction

Top left perspective illustration of a glide plane. Other images printed and graphical symbols for glide planes perpendicular to a and c with different glide directions. z = height of the point in the unit cell... 

The hexaboride crystal structure is related to the CsCl structure so by analogy the glide planes are (100) and the glide directions are (100). At the cores of glide disloca-tions the structure becomes quasi-hexagonal. 

It may be apparent from studying the perovskite structure that it is likely to exhibit quite anisotropic plastic (hardness) behavior, and it does. The primary glide plane is (110) and the glide direction is (1-10). 

J axis in direction b, glide plane perpendicular lo b with glide direction c... 

In the ac projection, the origin and axes are again chosen to conform with a right-handed axis set. The screw axes are now represented by the symbol that shows them to be perpendicular to the projection plane. The glide planes are now shown by the symbol at the upper left, which gives both the elevation (y = i and, by implication, 5) and glide direction (c). 

The combination of reflection and translation gives a glide plane. If the gliding direction is parallel to the a axis, the symbol for the axial glide plane is a and the operation is reflection in the plane followed by translation parallel to the a axis by a/2 . Similar axial glide planes b and c have translation components of b/2 and c/2, respectively. 

Another apparent anomaly in the plastic behaviour of ice is the absence of any preferred glide direction in the basal plane. Metals glide preferentially in the most closely packed direction of the most closely packed plane and we might expect similar preference for glide in the directions in ice, since the necessary dislocations exist. Instead of his, the glide is nearly isotropic in the... 

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