Crystallography is the science that studies the arrangement of atoms in crystals and is essential in various fields like pharmaceuticals and biochemistry. X-ray crystallography plays a critical role in determining the atomic structure of crystals, relying on principles such as Bragg's law, which describes how x-rays diffract off crystal surfaces. Key figures in this field include Sir William Lawrence Bragg, who pioneered x-ray crystallography, and Victor Goldschmidt, known for his contributions to crystal chemistry.

1. BASIC
CRYSTALLOGRAPHY
EARTH AND LIFE SCIENCE

2. DEFINITION
Crystallography is the branch of science that deals with
discerning the arrangement or sequence of the atoms’ bonding
as well as its geometric structure of its crystal lattices

3. DEFINITION
Crystallographers uses the properties and inner structures of
crystals to determine the arrangement of atoms and share the
known information or data to other scientific professionals such
as chemists, physicists, pharmacists, biochemists, etc.

4. DEFINITION
The pharmaceutical and biochemical fields rely extensively on
crystallographic studies. Many important pharmaceuticals are
administered in crystalline form, and detailed descriptions of
their crystal structures provide evidence to verify claims in
patents.

5. X-RAY CRYSTALLOGRAPHY
▪ A branch of crystallography that determines the atomic and
molecular structure of a crystal in three-dimensional (3-D)
space
▪ Fundamental in the development of many scientific fields
▪ Principle: A beam of X-Rays causes the crystal to diffract into
different directions

6. X-RAY CRYSTALLOGRAPHY
▪ The arrangement of the atoms needs to be in an ordered,
periodic structure in order for them to diffract the x-ray
beams.

7. SIR WILLIAM LAWRENCE BRAGG
▪ British physicist and crystallographer
▪ At age 25, he became the youngest recipient of the Nobel
Laureate for Physics
▪ He observed the diffraction pattern that could be used in
determining the atom’s position of the crystal
▪ He became a pioneer of X-Ray Crystallography

8. BRAGG’s LAW
When the x-ray is incident onto a crystal surface, its angle of
incidence, θ, will reflect back with a same angle of scattering, θ.
And, when the path difference, d, is equal to a whole number, n,
of wavelength, a constructive interference will occur.

9. BRAGG’s LAW
𝑛λ = 2𝑑 sin 𝜃
•λ is the wavelength of the x-ray,
•θ is the incident angle (the angle between incident ray and the scatter
plane), and
•n is an integer
•d is the spacing of the crystal layers (path difference),

10. PETER JOSEPH DEBYE
▪ Dutch-American physicist
▪ He studied under theoretical physicist, Arnold Sommerfield in
Aachen University of Technology
▪ Solved the effect of temperature on X-Ray diffraction patterns
of crystalline solids

11. VICTOR GOLDSCHMIDT
▪ “Founder of Modern Geochemistry and Crystal Chemistry”
▪ Studied the courses of Inorganic chemistry, geology,
mineralogy, physics, mathematics and zoology at University of
Oslo
▪ He was one of the scientists who developed rules for
eliminating chemically unlikely structures and for determining
the relative sizes of atoms.

12. ANGSTROM (Å)
▪ Named after Andres Jonas Ångström, a Swedish physicist
▪ Unit of measurement used in X-Ray crystallography
▪ 1 Å = 0.1 nanometers or 10−10
𝑚𝑒𝑡𝑒𝑟𝑠

13. SINGLE X-RAY DIFFRACTION
MEASUREMENT
▪ The crystal must be larger than 0.1 millimeter in all
dimensions with no internal imperfections
▪ Then, it is mounted on a goniometer, a tool used to accurately
record the angular position of an object
▪ The crystal is illuminated with a finely
focused monochromatic beam of X-rays, producing
a diffraction pattern of regularly spaced spots known
as reflections.