X-ray Diffraction Laboratory



X-ray powder diffraction is a scientific tool to elucidate structural characteristics in materials.  X-rays that are directed at crystalline powders or polycrystalline materials will scatter in a pattern that is unique to that material.  As such, a material can be identified by its scattered pattern and the pattern can be used as unambiguous evidence of discovery or for quantitative analysis.

 

Powder diffraction is a bulk sample procedure and can be employed to identify solids and heterogeneous samples and can be used to monitor solid-state reactions.  Amorphous materials will also scatter X-rays and the amorphous patterns are useful information to the solid-state scientist.  

 

 

The X-ray powder pattern for Vitamin C (ascorbic acid) is shown below.  Compare the Vitamin C pattern to the chemically similar compound salicylic acid (pre cursor to aspirin).  It is clear that the powder patterns are different and that an investigator can employ such patterns to establish the true chemical identity of an unknown powder.

 

Vitamin C :   salicylic acid :

 

Vitamin C Powder Pattern

powder

 

 

 

Salicylic Acid Powder Patten

 

aspirn

 

 

 

Comparison of Vitamin C powder pattern to Salicylic acid powder pattern.

 

 

compare