Chapter 3 Outline

Question 1

What type of solids are most solids (structure-wise)?

Answer 1

crystalline

Question 2

What is short-range order?

Answer 2

local arrangement of nearest-neighbor atoms around a central atom

Question 3

What is long-range order?

Answer 3

orders over distances much greater than the bond length

Question 4

What range order who amorphous solids show? (in 3D)

Answer 4

• Short-range order in 3D, but no long-range order

Question 5

What range order who crystalline solids show? (in 3D)

Answer 5

• show both short-range order and long-range order in 3D

Question 6

Are most metals amorphous or crystalline?

Answer 6

crystalline?

Question 7

What structure do ceramics and polymers have (crystalline, amorphous, etc.)?

Answer 7

either crystalline, amorphous or a combination

Question 8

How many lattice types does each crystal belong to?

Answer 8

one and only one

Question 9

Lattice definition

Answer 9

A 3D array of lattice points, each of which has identical surroundings (mathematically latencies can extend to infinity)

Question 10

What are lattice points?

Answer 10

vertices of a unit cell

Question 11

What are lattice parameters?

Answer 11

lengths of the unit cell edges

Question 12

What is a unit cell?

Answer 12

• the smallest representation of a material. - - In crystals, it is the smallest patterned collection of atoms or ions that repeat in space

Question 13

What determines what class a lattice type belongs to?

Answer 13

the lengths and angles within a unit cell

Question 14

Cubic Lattice axial lengths and angles

Answer 14

Axial Lengths: a=b=c
Angles: ⍺=β=γ=90

Question 15

Cubic bravais lattice

Answer 15

SC, BCC, FCC

Question 16

Tetragonal axial lengths and angles

Answer 16

Axial lengths: a=b≠c
Angles: ⍺=β=γ=90

Question 17

Tetragonal bravais lattice

Answer 17

SC, BCC

Question 18

Cubic Lattice symbol

Answer 18

P, I, F

Question 19

Lattice symbols meanings

Answer 19

P = primitive
I = body-centered
F = face centered
R = rhombohedral

Question 20

Tetahredral lattice symbol

Answer 20

P, I

Question 21

Orthorhombic axial lengths and angles

Answer 21

Axial Lengths: a≠b≠c
Angles: ⍺=β=γ=90

Question 22

Orthrombic bravais lattice

Answer 22

SC, BCC, FCC, Base

Question 23

Orthrombic lattice symbol

Answer 23

P,I,C,F

Question 24

Rhombohedral axial lengths and angles

Answer 24

Axial lengths: a=b=c
Angles: ⍺=β=γ≠90

Question 25

Rhombohedral bravais lattice

Answer 25

SC

Question 26

Rhombohedral lattice symbol

Answer 26

R

Question 27

Hexagonal axial lengths and angles

Answer 27

Axial lengths: a=b≠c Angles:⍺=β=90, (γ=120)

Question 28

Hexagonal bravais lattice

Answer 28

SC

Question 29

Hexagonal lattice symbol

Answer 29

P

Question 30

Monoclinic axial lengths and angles

Answer 30

Axial lengths: a≠b≠c Angles: ⍺=γ=90 (β≠90)

Question 31

Monoclinic bravais lattice

Answer 31

SC, Base

Question 32

Monoclinic lattice symbol

Answer 32

P,C

Question 33

Triclinic Axial lengths and angles

Answer 33

Axial lengths: a≠b≠c Angles: ⍺≠β≠γ

Question 34

Triclinic bravais lattice

Answer 34

SC

Question 35

Triclinic lattice symbol

Answer 35

P

Question 36

Simple cubic lattice description

Answer 36

atoms located in each corner

Question 37

How many bravais lattices are there?

Answer 37

- 14 - categorized P,I,F,(A,B,C),R

Question 38

Simple cubic lattice description

Answer 38

atoms located in each corner

Question 39

Body-centered cubic lattice description

Answer 39

atoms at each corner plus one in the center of the 6 faces

Question 40

Face-centered cubic lattice description

Answer 40

atoms at each corner in the center of each of the 6 faces

Question 41

Base-centered lattice description

Answer 41

rectangular with atoms at each corner and one in the center of the top and bottom faces

Question 42

Simple hexagonal lattice description

Answer 42

8 faces

Question 43

hexagonal close-packed lattice description

Answer 43

- a variation of SH - Ideally has 6 atoms per cell

Question 44

How are directions, planes, and families of planes represented by vectors?

Answer 44

Directions: [] brackets; negative numbers represented by bar over the number planes: () brackets families of planes: {} brackets

Question 45

How to calculate planes?

Answer 45

1. intercept position on axis 2. reciprocal of intercept 3. Reduce all fractions by multiplying all values until they are all whole numbers

Question 46

How can angles between two directions be determined?

Answer 46

by taking the vector dot product A*B= |A||B|cos ⍬

Question 47

Atomic packing factor equation

Answer 47

volume of atoms in the unit cell / volume of the unit cell = (# atoms in cell) *( volume of an atom)/ volume of the unit cell

Question 48

What are intersticies?

Answer 48

the largest holes between the atoms in a lattice

Question 49

Where are interstices in FCC Latticies? How many sites per cell?

Answer 49

- at the center of the unit cell and center of each edge - 4 sites per unit cell

Question 50

Where are the interstices in BCC lattices? How many sites per cell?

Answer 50

- at the center of each face and the center of each edge - 6 sites per unit cell

Question 51

How do waves undergo constructive interference/ diffraction?

Answer 51

- 2 waves of equal amplitude and are in phase collide - the amplitude of the composite wave is 2x that of the components, causing diffraction

Question 52

What is destructive wave interference?

Answer 52

when the composite wave is equal to zero at all points

Question 53

Bragg's Law equation? What does it describe?

Answer 53

2dsin⍬=nλ - when the x-ray is incident onto a crystal surface, its angle of incidence, θ, will reflect back with a same angle of scattering, θ

Question 54

What is linear density?

Answer 54

the number of atoms centered along a direction within one unit cell/ length of the line contained within one unit cell

Question 55

What is planar density?

Answer 55

the number of atoms centered on a plane one cell/ are of the plan contained within one unit cell

Question 56

CHAtomic packing factor definition

Answer 56

volume of atoms in the unit cell per unit volume