solids and liquids the microstructure of solids. 2 16.2 the microstructure of solids which one of...

Solids and Liquids

The Microstructure

of Solids

2 16.2 The Microstructure of Solids

Which one of these is not a crystal?

3 16.2 The Microstructure of Solids

Glass is not a crystal but an amorphous solid!

4 16.2 The Microstructure of Solids

Condensed matter:Atoms or molecules are closely packed and interact with each other

Atoms or molecules do not interact with each other, except for collisions

5 16.2 The Microstructure of Solids

Fixed volume

No

Yes

Yes

Fixed shape

No

No

Yes

6 16.2 The Microstructure of Solids

Microstructures

microstructrure: the spatial arrangement of atoms and molecules in matter.

Solids have one of two possible microstructures

Amorphous solidNo repeating pattern,or long-range order

Crystalline solidOrdered pattern,

like bricks in a wall

7 16.2 The Microstructure of Solids

Microstructures

Solids have one of two possible microstructures

Amorphous solidNo repeating pattern,or long-range order

Crystalline solidOrdered pattern,

like bricks in a wall

Glasses and most plastics are amorphous solids

8 16.2 The Microstructure of Solids

Microstructures

Solids have one of two possible microstructures

Amorphous solidNo repeating pattern,or long-range order

Crystalline solidOrdered pattern,

like bricks in a wall

Glasses and most plastics are amorphous solids

Crystalline solids include minerals,

gemstones, metals and even

some plastics

9 16.2 The Microstructure of Solids

Crystals

Crystal structures describe:

- the distance between atoms or molecules

- bond angles between atoms or molecules

The salt in your salt shaker is made of little cubic crystals!

NaCl crystal

10 16.2 The Microstructure of Solids

Water molecules align in six-sided rings

The microscopic arrangement of molecules in

a crystalline solid can show up in the shape of an object!

Snowflakes have six-way symmetry

Crystals

11 16.2 The Microstructure of Solids

Amorphous solids

A-morph-ous

“without” “shape”

Glasses do not have an ordered structure.

Over time, they will sag or deform under their own weight

Most glasses are oxide glasses, because they are made mostly of

silicon dioxide (silica)

12 16.2 The Microstructure of Solids

Amorphous solids

A-morph-ous

“without” “shape”An amorphous solid is like an “immobile” liquid.

As the temperature rises, the amorphous solid becomes softer and behaves more like a liquid.

Crystals only melt at one temperature.Glass is an amorphous solid

13 16.2 The Microstructure of Solids

Amorphous solids

Some solids are metallic glasses

By cooling down a metal very, very fast, you can freeze its atoms into a glass.

Fancy golf club have heads made of metallic glass, because they transmit energy very well

14 16.2 The Microstructure of Solids

Crystal structures

A crystal structure describes exactly the 3D repeating

pattern of atoms and molecules

Some crystals are square (table salt),

some are hexagonal (quartz and snowflakes)

15 16.2 The Microstructure of Solids

Crystal structures

Bravais lattices: fourteen groups of crystal structures used to help group the many different types of crystal structures.

16 16.2 The Microstructure of Solids

Crystal structures

Calcite, a rhombohedral crystal

If they are undisturbed during cooling, crytalline materials tend to

form solids along the same geometry as their structure

17 16.2 The Microstructure of Solids

Crystal defects

Did you know that the

beautiful colors in

gemstones come from

crystal defects?

Ruby

Sapphire

Both sapphires and rubies are

crystals of aluminum oxide

(Al2O3) that contain different types

and amounts of impurities

18 16.2 The Microstructure of Solids

Crystal defects

Crystals are 3-D structures,

so defects can occur in up to

three dimensions

Defects in a crystal structure

affect the properties of the crystal

19 16.2 The Microstructure of Solids

Crystal defects

0-D defects1-D defects

2-D defects

Point defects (0-D) occur when one atom is different from the rest of the crystal

Vacancy:an atom is missing

from the crystal structure

Interstitial:an extra atom is wedged in

between others

Substitutional:a different type of atom

or molecule from the rest of the crystal

structure is present

20 16.2 The Microstructure of Solids

Crystal defects

0-D defects1-D defects

2-D defects

The color of ruby comes from

chromium (Cr) substitutional defects

Substitutional:a different type of atom

or molecule from the rest of the crystal

structure is present

Ruby

Al2O3

Chromium atom

21 16.2 The Microstructure of Solids

Solids have one of two possible microstructures

Amorphous solidNo repeating pattern,or long-range order

Crystalline solidOrdered pattern,

like bricks in a wall