Chapter 12 - Solids and Modern Materials

Metallic solids

Held together by a sea of collectively shared electrons

Ionic solids

Sets of cations and anions mutually attracted to one another

Covalent-network solids

Joined by an extensive network of covalent bonds

Molecular solids

Discrete molecules held together by weak forces

Polymers

Contain a long chain of atoms connected by covalent bonds

Nanomaterials

Crystalline compounds with the crystals on the order of 1-100nm

Crystalline

Solids with a repeating pattern of atoms

Amorphous

Lack of order in the arranged atoms

Unit cell

The basis of a repeating pattern

Crystal lattice

Geometric pattern on which the unit cell is

Lattice points

Positions that define the overall structure of the crystalline compound

Centered lattices

Have atoms in another regular location, most common in the body center (body-centered) or center of the face (face-centered)

Alloys

Materials that contain more than one element and have the characteristic properties of metals

Substitutional alloys

A second element takes the place of a metal atom

Interstitial alloys

A second element fills a space in the lattice of metal atoms

Heterogeneous alloys

Components are not dispersed uniformly

Electron sea model

Where we assume a metal is a group of cations suspended in a sea of electrons

Molecular solids

Consist of atoms of molecules held together by weaker forces

Shape

Ability to stack, it has influence on some physical properties like boiling point

Covalent-network solids

Atoms are covalently bonded over large network distances with regular patterns of atoms

Coordination number

The number of nearest-neighbor atoms of an atom

Polymers

Molecules of high molecular weight made by joining smaller molecules called monomers

Addition

Formed when a bond breaks and the electrons in that bond make two new bonds

Condensation

Formed when a small molecule is removed between two larger molecules

Copolymers

Formed by two different monomers

Quantum dots

Semiconductor particles that are about 1-10nm

Bond energy

Gap between highest occupied level and lowest unoccupied level

Buckminsterfullerene or Buckyballs

Soccer ball-shaped C60 molecule