Chapter 2: Atomic Structure and Interatomic Bonding
– Magnitude of force is a function of interatomic
– The bond‐length corresponds to the distance
at which the attractive and repulsive forces
– Minimum energy is
called the bond energy. (Energy that is
required to completely separate two
- High bonding energy = High melting Temperature
- When one element loses electrons and the
other gains electrons. The resulting ions attract
and form a strong bond. Ionic Bond
- Stable electron configuration is achieved
by sharing/overlap of outer orbitals. Covalent Bd
- Metallic Bond = metals bonding
-Secondary Bonding = weak bd
Aka van der Waals bond
Chapter 3: The structure of crystalline solids
Polymorphic: has more than one crystal structure
Miller Direction Indices:-
1. Start at any cell corner.
2. Find coordinates of vector in units of a, b, c.
3. Multiply or divide all the coordinates by a common factor.
– To reduce all the coordinates to the smallest possible integer values.
4. Represent as [ u v w]
– no commas
5. Represent negative directions as ū.
Miller Plane Indices:-
– Choose a starting point so that the plane does not pass
through the origin.
– Find the intercepts in units of x, y, z, planes parallel to an axis
have an intercept at infinity.
– Find the reciprocals of the intercepts: 1/x, 1/y, 1/z.
– Multiply or divide by common factor to get the smallest
possible integer values.
– Represent the index as(h k l) – no commas.
Example for famalies of direction etc:
Which of the following planes contains all of the following directions ,
Solution: Take each choice and do DOT PRODUCT with the directions in the
question and see which option give you a DOT PRODUCT of 0.
Most materials contain many crystals called grains = polycrystal /
The region of atomic mismatch where grains meet is called a grain
The physical properties of a material differ depending on the
crystallographic direction in which the measurement is taken – Anisotropy
Isotropic: Properties which are independent of the direction of
measurement are referred to as being isotropic.
o As structural symmetry decreases, anisotropy increases
• X‐Rays help determine atomic interplanar distances and crystal structures
• A form of electromagnetic Radiation with high energy and short
Diffraction: Constructive Interference of x‐ray beams that are scattered by
atoms of a crystal.
Crystals diffract X-rays
Bragg’s law says constructive interference will occur if the extra path is a
multiple of the wavelength:
n=1,2,3 (if not indicated 1st order reflection)
a= lattice parameter