[PHYPHARM-FINALS] SOLIDS AND THE CRYSTALLINE STATE

Solids

This is one of the fundamental states of matter, alongside liquid, gas, and plasma.

Solids

• Fixed shape and volume.

• Particles are closely packed and vibrate in place.

• Strong intermolecular forces keep particles in position.

Amorphous Solid and Crystalline Solid

What are the two general types of solids?

Crystalline Solids

Property

Particle Arrangement: Highly ordered, repeating 3D lattice

• Highly ordered

• Repeating 3D lattice

What is the particle arrangement of crystalline solids?

Crystalline Solids

Property

Long-range order: Present

Crystalline Solids

Property

Melting Point: Sharp and well-defined.

Crystalline Solids

Property

Shape: Regular geometric forms (e.g., cubes, prisms)

Crystalline Solids

Property

Cleavage: Breaks along specific planes.

Crystalline Solids

Property

Anisotropy: Yes (properties vary with direction).

• Salt (NaCl)

• Quartz

• Diamond

Examples of Crystalline Solids.

• Electronics

• Optics

• Pharmaceuticals

Uses of Crystalline Solids.

Amorphous Solids

Property

Particle Arrangement: Random, disordered arrangement.

Random, disordered arrangement

What is the particle arrangement of Amorphous Solids?

Amorphous Solids

Property

Long-range order: Absent

Amorphous Solids

Property

Melting Point: Gradual over a temperature range.

Amorphous Solids

Property

Shape: Irregular, no definite shape

Amorphous Solids

Property

Cleavage: Breaks irregularly

Amorphous Solids

Property

Anisotropy: No (isotropic—same in all directions).

• Glass

• Plastic

• Rubber

Examples of Amorphous Solids.

• Packaging

• Lenses

• Coatings

Uses of Amorphous Solids.

• Ionic

• Covalent

• Molecular

• Organic

• Metallic

What are the five types of crystals?

Ions

What is the constituent units of Ionic Crystals?

Na and Cl in NaCl

Example of ions:

Electrostatic Attraction

Bonding Type of Iodine Crystals:

Ionic Crystals

Properties:

Hard, brittle, high melting points

Atoms

What is the constituent units of Covalent Crystals?

Diamond and graphite

Examples of atoms:

Covalent Bond

Bonding Type of Covalent Crystals:

Covalent Crystals

Properties:

Hard, brittle, high melting points

Molecules

What is the constituent units of Molecular Crystals?

• CO₃

• Benzene

• Chloroform

• Naphthalene

Examples of molecules:

• Van der Waals Forces

• Hydrogen Bonding

Bonding Type of Molecular Crystals:

Molecular Crystals

Properties:

Soft, low melting points

• Aliphatic hydrocarbons

• Fatty acids

What are the constituent units of Organic Crystals?

• Van der Waals Forces

• Hydrogen Bonding

Bonding Type of Organic Crystals:

Organic Crystals

Properties:

Chain ends arranged parallel; fatty acids form layers or dimers.

Positive ions in electron gas

What is the constituent units of Metallic Crystals?

Metallic Bonding

Bonding Type of Metallic Crystals:

Metallic Bonding

Properties:

Good electrical conductors; hardness and melting point vary with lattice defects.

Metallic Bonding

Delocalized electrons.

X-rays

Principle

These are diffracted by crystals, similar to how visible light is dispersed by a ruled grating.

Crystals

X-rays are diffracted by?

X-ray wavelengths

Why It Works

These are comparable to atomic/molecular distances in crystals.

Atomic/molecular distances in crystals

X-ray wavelengths are comparable to?

Sensitive plate placed behind the crystal

Method

Diffraction pattern is photographed on a?

Reflection of x-rays

Modified Technique

Uses ____ from atomic planes to measure interplanar distances in the lattice.

Structure and atomic arrangement

Applications

Determines crystal ___ and _____ of various compounds.

X-ray Diffraction

This is used when whole crystal are unavailable or unsuitable for analysis.

• Cubic

• Tetragonal

• Hexagonal

• Rhombohedral

• Monoclinic

• Triclinic

6 Distinct Systems of Crystals:

Sodium chloride

What is the compound of Cubic?

Urea

What is the compound of Tetragonal?

Iodoform

What is the compound of Hexagonal?

Iodine

What is the compound of Rhombohedral?

Sucrose

What is the compound of Monoclinic?

Boric Acid

What is the compound of Triclinic?