XRD

Question 1

Components of XRD

Answer 1

X-ray cathode tube
Sample holder
X-ray detector

Question 2

What is Bragg’s Law

Answer 2

X-rays will only occur if the way the x-rays and substances interact meet the conditions of Bragg’s Law.
2dsin @ = nL
d: interplanar spacing
@ : Bragg’s Angle / angle of incidence
n : order of reflection
L: wavelength of X-ray source

Question 3

Bragg’s Law requirements

Answer 3

1. The angle of incidence is equal to the angle of scattering
2. The path length difference is equal to an integer number of wavelengths

Question 4

What will XRD measure

Answer 4

1. Yields information on how the actual structure deviates from the ideal one
2. Measure the average spacing between layers of rows of atoms in a substances
3. Determine the orientation of an individual grain or crystal
4. Measure the size, shape and internal stress of small crystalline areas
5. Identify the crystal structure of unknown substances