chapter 3 from lecture notes

Question 1

A crystalline material must have a fundamental_____(fill in the blank) which is then repeated in 3D throughout the material

Answer 1

Unit cell

Question 2

Different material have unique ____ and ____ of the fundamental unit cell

Answer 2

1) shape 2) size

Question 3

what is lattice parameter ?

Answer 3

measure of physical length and size of the unit cell

Question 4

What is the simplest cubic structure ?

Answer 4

BCC

Question 5

What is lattice parameter of BCC? How many atoms does it have ?

Answer 5

Lattice parameter =a=4R/sqrt(3)

There are total of 2 atoms per bcc crystal structure
1 atom at the centered
8x1/8 from the corner
total 2

Question 6

What is FCC latice parameter ? How many atoms does it have ?

Answer 6

a=2Rsqrt(2)
there are 0 interior atoms
there are 8x1/8=1 atoms from the corner
number if face centered atoms=6x1/2=3
in total there are 4 complete atoms

Question 7

Describe facts about hexagonal lattice parameter?

Answer 7

A common non-cubic crystal lattice where planes are stacked on top of each other.

It has two lattice parameter
a=length of hexagon
c=height of the hexagon crystal structure

it has total of 6 atoms
12x1/6 of corner atoms =2
2x1/2=1 face atoms
3x1=3 number of interior atoms

Question 8

The higher the linear or planar density, the closer the atoms are, and can interact with each other. T/F

Answer 8

T

Question 9

what are the densest plane in each FCC,HCP AND BCC and their atomic packaging factor rank them in order

Answer 9

FCC ( most densit) =(111) apf=0.74
HCP(2nd most densit)=(0001) apf=0.74
BCC(3rd most dense ) = (110) apf 0.68

Question 10

X-ray diffraction question when will peak of FCC and BCC will happen ?

Answer 10

BCC peak will happen if h+k+l = even
FCC peak will happen if h,k,l are all odd or even