Solid States

Question 1

What are the types of solids

Answer 1

Metallic, ionic, simple covalent and covalent lattice

Question 2

Define lattice

Answer 2

A regular, periodic array of points in space

Question 3

Define unit cell

Answer 3

Smallest repeat unit that describes a lattice

Question 4

What is the name of the 14 lattices

Answer 4

Bravais lattices

Question 5

What do P, I, F and C stand for in the bravais lattices

Answer 5

Primitive
I - body centred
F - all face centred
C - one face centred

Question 6

How many neighbours do close packed structures have

Answer 6

6

Question 7

What are the 2 types of close packing

Answer 7

ABA - hexagonal

ABC - cubic

Question 8

What is the coordination number of a close packed structure

Answer 8

12

Question 9

Why are ccp softer than hcp

Answer 9

More slip planes in ccp

Question 10

What are the cubic unit cells and draw them

Answer 10

Bcc, Fcc/ccp, primitive

Question 11

What is the coordination number for primitive

Answer 11

6

Question 12

What is the coordination number for FCC

Answer 12

12

Question 13

What is the coordination number for bcc

Answer 13

8

Question 14

Why is bcc harder than hcp/ccp

Answer 14

It is harder for the atomic planes to slip over each other

Question 15

What is Pythagoras Theorem

Answer 15

B^2 = 2a^2
B = root 2 a
C^2 = 3a^2

Question 16

How many atoms are in a ccp unit cell

Answer 16

4

Question 17

What is the equation for volume of atoms in a unit cell

Answer 17

Number of atoms x 4/3 pir3

Question 18

What is the volume of a unit cell

Answer 18

L^3 = 8^3/2 r3

Question 19

What is packing efficiency

Answer 19

Volume of atoms / volume of unit cell x 100

Question 20

Calculate packing efficiency of bcc

Answer 20

Work it out!

Question 21

What is density

Answer 21

Number of atoms x RAM / Na

Question 22

What is the hole in a lattice called

Answer 22

Interstitial site

Question 23

What are the 2 main types of holes

Answer 23

Octahedral and tetrahedral

Question 24

How many octahedral sites are there in ccp

Answer 24

4
1 centred
12 on edges 1/4
They sit in the 1/2 level

Question 25

How many tetrahedral sites are there

Answer 25

8 fully centred sit at 1/4 and 3/4 level

Question 26

What is a coordination number

Answer 26

Number of nearest neighbours

Question 27

What is coordination geometry

Answer 27

Shape of polyhedron formed by neighbouring atoms

Question 28

What is the coordination geometry of CaF2

Answer 28

FCC wrt to Ca ions | F in tetrahedral holes

Question 29

What is the geometry of CsCl

Answer 29

Primitive cube wrt cl | Cs in cubic interstitial

Question 30

How do you calculate empirical formula

Answer 30

Centre - 1 Face - 1/2 Edge -1/4 Corner 1/8

Question 31

What is the radius ratio

Answer 31

The rule used to predict structure r+/r-

Question 32

What are the favoured interactions in an ionic solid

Answer 32

Maximise anion cation | Minimise like to like

Question 33

What is lattice enthalpy

Answer 33

Solid form to gasious ions

Question 34

What is the issue with lattice enthalpy in regards to determining shape

Answer 34

The thermodynamic parameters are not always known

Question 35

What is the Madelung constant

Answer 35

A - the distance between all of the atoms not just one

Question 36

What does the Born- Mayer include

Answer 36

That ions are not point charges and are surrounded by electron clouds which interact P - compressibility constant

Question 37

What is the Kapustinskii equation

Answer 37

Latt = KVZ-Z+/ r-r+

Question 38

How far does Kapustinskii work

Answer 38

Good for pure ionic hard-hard

Question 39

What are miller indices

Answer 39

The reciprocal of the coordinates

Question 40

How do you calculate the separation between each plane

Answer 40

H^2/a^ + k^2/b^2....

Question 41

What is constructive interference

Answer 41

When the 2 planes are in phase and the wave length increases by a whole number

Question 42

What is destructive interference

Answer 42

When the 2 planes do not produce waves in the same phase giving a wave length difference of /2

Question 43

What is Bragg equation

Answer 43

Lambda = 2asin theta/ root (h^2...)

Question 44

How can we use X-ray diffraction to determine structure

Answer 44

Find the systematic absences and compare to ladder of each structure