Crystalline materials have a repeating, oriented structure where properties like melting points are well-defined, while amorphous materials have an irregular, non-repeating structure without distinct properties. Polymers typically form amorphous structures, while drugs can more easily crystallize as smaller, well-defined molecules, though they are not always crystalline. Crystals are useful for determining molecular structures and usually indicate high purity, an important factor for medicines.

1. 1. List two differences between crystalline material and one with an amorphous structure.
Solution
In crystalline matter everything is oriented in an identical repeating matter. For example, an
auditorium where everyone is regularly spaced and all facing the same way can be thought of as
a "2d crystal." In amorphous structure everything is irregularly oriented and does not have
regular spacings. Crystalline materials have very well defined properties (melting points, optical
properties, diffraction), and amorphous materials do not (no distinct melting points, more
complicated optical properties, etc.).
With specific regards to durgs or polymers, most polymers form amorphous materials. Drugs,
being smaller and well-defined molecules, can be crystallized much more easily, although they
are not necessarily crstalline. However, crystals are useful for determining structures, and usually
correlate very well with high purity, which is very desirable with medicines.