Week 4: Structure of Crystalline Solids

Question 1

What does the coordination number refer to?

Answer 1

The neighbouring cells that the unit cell has nearby.

Question 2

What does the APF relate to?

Answer 2

The atomic packing factor can tell us about the strength and the density of a solid.

It’s a ratio between the volume of the atoms in the unit cell to the volume of the unit cell.

Question 3

What are the 4 most common metallic crystal structures?

Answer 3

FCC
BCC
SC
HCP

Question 4

Polycrystal

Answer 4

A material where each grain is a single crystal and they’re all randomly oriented.

Question 5

What is the edge length of SC?

Answer 5

2R

Question 6

What is the edge length of BCC?

Answer 6

4R / √3

Question 7

What is the edge length of FCC?

Answer 7

R * (2√2)

Question 8

What is the edge length of HCP?

Answer 8

c/a = 1.633

Question 9

What is the atoms per unit cell in SC?

Answer 9

1

Question 10

What is the atoms per unit cell in BCC?

Answer 10

2

Question 11

What is the atoms per unit cell in FCC?

Answer 11

4

Question 12

What is the atoms per unit cell in HCP?

Answer 12

6

Question 13

What is the APF% in SC?

Answer 13

52%

Question 14

What is the APF% in BCC?

Answer 14

68%

Question 15

What is the APF% in FCC?

Answer 15

74%

Question 16

What is the APF% in HCP?

Answer 16

74%

Question 17

What’s an example of SC metal?

Answer 17

Po = Polonium

Question 18

What’s an example of BCC metal?

Answer 18

Fe = Iron

Question 19

What’s an example of FCC metal?

Answer 19

Al = Aluminium

Question 20

What’s an example of HCP metal?

Answer 20

Zn = Zinc

Question 21

What is the density for solid metallic crystals?

Answer 21

Mass of atoms in the unit cell / Total volume of unit cell

Question 22

What’s the coordination number of SC?

Answer 22

6

Question 23

What’s the coordination number of BCC?

Answer 23

8

Question 24

What’s the coordination number of FCC?

Answer 24

12