Definition of crystal Habit

Definition of crystal Habit:

-A crystal habit is defined as the description of the outer appearance of a crystal whereas the internal structure is the molecular arrangement within the solid.

-Any crystal is characterized by its internal structure and habit.

-Crystal habit can also be modified by adding impurities or ‘poisons’; for example, sulphonic acid dyes alter the crystal habit of ammonium, sodium and potassium nitrates.              

-It can be quantitatively expressed in terms of aspect ratio (AR), defined as the ratio of length to width and values of AR approaching 1 (spherical or cube shape) are considered to be pharmaceutically good. It is preferable to keep the AR values below 5 so as to avoid problems with flow. AR in polar solvents was as high as 9.4 in comparisons with 5-6 in non-polar solvents.