Structure of Crystalline Solids - Chapter 4 Flashcards Preview

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Flashcards in Structure of Crystalline Solids - Chapter 4 Deck (18):
1

Coordination number of BCC?

8

2

Unit number of atoms in BCC?

2

3

Unit number of atoms formula?

N = Ni + Nf/2 + Nc/8

4

Atomic packing factor of BCC?

0.68

5

FCC:

Face Centered Cubic Structure

Atoms located at each of the corners and the centers of all the cube faces.

6

Three Main Crystal structures:

FCC - Face-centered structure
BCC - Body-centered structure
HCP -

7

FCC cube length a?

a = 2R* Sqrt[2]

8

FCC coordination number?

12

9

Unit number of atoms in FCC?

4

10

Atomic Packing Factor of FCC?

0.74

11

Atomic Packing Factor(APF)?

The APF is the sum of the sphere volumes of all atoms within a unit cell divided by the unit cell volume.

APF = Volume of atoms in a unit cell/total unite cell volume

12

BCC:

Body centered cubic structure:

Atoms located at all eight corners and a single atom at the cubic center.

13

BCC unit cell length a?

a = 4R/Sqrt[3]

14

HCP:

Hexagonal close-packed:

The top and bottom faces of the unit cell consists of six atoms that form regular hexagons and surround a single atom in the center. Another plane that provides three additional atoms to the unit cell is situated between the top and bottom planes.

15

Number of atoms per unit cell for HCP:

N = Ni + Nf/2 + Nc/6

16

Unit number of atoms in HCP:

N = 3 + 2/2 + 12/6 = 6

17

Coordination number of HCP?

12

18

Atomic packing factor of HCP?

0.74