Chapter 3 - Crystal Structures

Question 1

Crystal

Answer 1

Solid composed of atoms, ions, or molecules arranged in a pattern that is repeated in three dimensions

Question 2

Amorphous Solid

Answer 2

Solid lacking in long-range atomic order

Question 3

Unit Cell

Answer 3

Repeating unit in crystal

Question 4

Lattice

Answer 4

An infinite 3D array of points having identical surroundings

Question 5

Crystal Systems

Answer 5

7 Unique Unit cell systems that can be stacked together 3-Dimensionally

Question 6

Bravais Lattice

Answer 6

14 possible arrangements of atoms in space

Question 7

FCC

Answer 7

Atoms Per Cell: 4     6 x (1/2) = 3
                                  8 x (1/8) = 1
CN: 12
APF: .74
LC: 2R√2
EX: Cu, Al, Ag, Au, Pt

Question 8

BCC

Answer 8

Atoms Per Cell: 2     8 x (1/8) = 1
                                   1 x (  1  ) = 1
CN: 8
APF: .68
LC: 4R/√3
EX:

Question 9

HCP

Answer 9

Atoms Per Cell: 6 3 x 1 = 3
2 x (1/2) = 1
12 x (1/6)=2
CN: 12
APF: .74
LC:
EX: Cd, Mg, Zn, Zr

Question 10

Coordination Number

Answer 10

Number of closest Molecules

Question 11

Atomic Packing Factor

Answer 11

Volume of atoms in Unit Cell
Divided by
Total Volume of Unit Cell

Question 12

Lattice Constant

Answer 12

Distance between atoms in a unit cell

Question 13

Miller indices are surrounded by _______ for directions

Answer 13

Square Brackets

ex: [1 1 1]

Question 14

Miller indices are surrounded by _______ for planes

Answer 14

Parenthesis

ex: (1 1 1)

Question 15

Miller indices are surrounded by _______ for indicies families

Answer 15

Angle Brackets

ex:

Question 16

Linear Atomic Density

Answer 16

=(# of atomic diameters intersected) / (Length of Line)

Question 17

Planar Atomic Density

Answer 17

(# or atoms whose centers are intersected) / ( Selected Area)