A5. The Solid State

Solids

These are characterized of having fixed shapes, nearly incompressible little kinetic energy, have strong intermolecular forces, very little kinetic energy. Their atoms vibrate in fixed positions about an equilibrium position, there is very little translational motion.

Crystalline

Fixed geometric pattern

Choices:

• Crystalline

• Amorphous

• Polymeric

Crystalline

Has definite MP

Choices:

• Crystalline

• Amorphous

• Polymeric

Crystalline

Anisotropic (different properties in various directions) except cubic crystals

Choices:

• Crystalline

• Amorphous

• Polymeric

Crystalline

Less soluble

Choices:

• Crystalline

• Amorphous

• Polymeric

Polymorphs, hydrates, solvates, salts

Examples of crystalline solids (4)

Amorphous

Randomly arrange molecules

Choices:

• Crystalline

• Amorphous

• Polymeric

Amorphous

Isotropic (properties are same in all directions)

Choices:

• Crystalline

• Amorphous

• Polymeric

Amorphous

No definite MP

Choices:

• Crystalline

• Amorphous

• Polymeric

Amorphous

More soluble

Choices:

• Crystalline

• Amorphous

• Polymeric

Polymeric

A special type that can exhibit crystalline and amorphous characteristics

Choices:

• Crystalline

• Amorphous

• Polymeric

NaCl

[Type of Crystalline Solids Based on Symmetry (Geometric shapes) according to Bavis]

Cubic

Urea

[Type of Crystalline Solids Based on Symmetry (Geometric shapes) according to Bavis]

Tetragonal

Sucrose, Ritonavir (I)

[Type of Crystalline Solids Based on Symmetry (Geometric shapes) according to Bavis]

Monoclinic

Boric acid

[Type of Crystalline Solids Based on Symmetry (Geometric shapes) according to Bavis]

Triclinic

Iodine

[Type of Crystalline Solids Based on Symmetry (Geometric shapes) according to Bavis]

Rhombic

Iodoform

[Type of Crystalline Solids Based on Symmetry (Geometric shapes) according to Bavis]

Hexagonal

Ritonavir (II)

[Type of Crystalline Solids Based on Symmetry (Geometric shapes) according to Bavis]

Orthorhombic

Isometric (or cubic)

All three axes are equal in length, and all are perpendicular to one another.

Choices:

• Isometric (or cubic)

• Tetragonal

• Orthorhombic

• Hexagonal

• Triclinic

• Monoclinic

• Rhombohedral (or trigonal)

Tetragonal

Two of the three axes are equal in length, and all three axes are perpendicular to one another.

Choices:

• Isometric (or cubic)

• Tetragonal

• Orthorhombic

• Hexagonal

• Triclinic

• Monoclinic

• Rhombohedral (or trigonal)

Orthorhombic

All three axes are unequal in length, and all are perpendicular to one another.

Choices:

• Isometric (or cubic)

• Tetragonal

• Orthorhombic

• Hexagonal

• Triclinic

• Monoclinic

• Rhombohedral (or trigonal)

Hexagonal

Of four axes, these are of equal length, are separated by equal angles, and lie in the same plane. The fourth axis is perpendicular to the plane of the other three axes. The cells have lattice points in each of the two six-sided faces.

Choices:

• Isometric (or cubic)

• Tetragonal

• Orthorhombic

• Hexagonal

• Triclinic

• Monoclinic

• Rhombohedral (or trigonal)

Triclinic

All three axes are unequal in length, and none is perpendicular to another.

Choices:

• Isometric (or cubic)

• Tetragonal

• Orthorhombic

• Hexagonal

• Triclinic

• Monoclinic

• Rhombohedral (or trigonal)

Monoclinic

All three axes are unequal in length, and two axes are perpendicular to each other.

Choices:

• Isometric (or cubic)

• Tetragonal

• Orthorhombic

• Hexagonal

• Triclinic

• Monoclinic

• Rhombohedral (or trigonal)

Rhombohedral (or trigonal)

All three axes are of equal length, and none of the axes is perpendicular to another, but the crystal faces all have the same size and shape.

Choices:

• Isometric (or cubic)

• Tetragonal

• Orthorhombic

• Hexagonal

• Triclinic

• Monoclinic

• Rhombohedral (or trigonal)

Polymorphism

A property of crystalline solids which is the ability of solid to exist in more than one crystalline form

Theobroma oil (cocoa butter)

Example of a substance that has the ability of solid to exist in more than one crystalline form

• 18 deg C

• 22 deg C

• 28 deg C

• 34.5 deg C

Give the MP of the ff:

• Gamma

• Alpha

• Beta prime

• Beta

Allotropy

A special case of polymorphism in elemental; substances

graphite, diamond, fullerene - all allotropes of Carbon

Example allotropic substances (3)

Enantiotropic; sulfur

A polymorphic change that is reversible; give an example

Monotropic; diamond → graphite

A polymorphic change that is unstable, change is one direction only; give an example

Iso

A polymorphic change that has similar properties in all directions

Anisotropic

A polymorphic change that has different properties in various directions

Pseudopolymorphs

Solvates are also known as

Solvates / Pseudopolymorphs

This occurs when residual solvents are trapped in crystalline lattice

Hydrates

solvates when water is the solvent

Anhydrates/Anhydrous

crystals with no water of crystallization

Anhydrous crystals

Which has higher aqueous solubility: anhydrous crystals or hydrates

supercooled liquids

Amorphous solids are also known as

Amorphous solids

Its molecules arranged in random manner and end to flow when subjected to sufficient

Glass, synthetic plastics

Examples of amorphous solids (2)

Vitrification Process

[Crystal to Amorphous Transformation] It involves heating or dissolution and quench cooling or fast solvent evaporation

Amorphization Process

[Crystal to Amorphous Transformation] It involves mechanical processing