Exam 1 Flashcards
Metals (Define, structure, properties)
One or more metallic elements (Crystalline Structure, Metallic bonds)
Stiff, ductile, good conductors, shiny, corrosion
Ceramics (Define, structure, Properties)
Compounds between metallic and non-metallic elements (Crystalline structure, metallic and nonmetal elements)
Stiff, brittle, poor conductors, resistant to degradation
Glass (Define, Structure, properties)
Inorganic amorphous solid (silica based)
Stiff, brittle, resistant to degradation, poor conductors
Polymer (Define, Structure, Properties)
Organic, long molecules, always amorphous with some crystalline areas
Poor conductors, can be either brittle or ductile.
Vacancy: Shcottley type
Displacing atoms, but still within rows
Vacancy Frenkel Type
Displacing atoms, but shoved in between them
Substitutional Impurities
Atoms are substituted with a different atom type
Interstitial Impurities
Atom is introduced and shoved between other atoms
(Introduced atom is typically much smaller, can fit between atoms easily)
Hume-Rother Rules (what are they for and what are the rules?)
Solubility for substitutional impurities
- Atomic size +/- 15%
- Electronegativity +/- 0.5
- Same/similar crystal structure
- Similar/same # of valence electrons +/- 1
How to calculated vectors
head - tail
No fractions
use bracket notation
overbar for negative numbers
How to calculate planes
one point @ a time
Extend the shape so each axis is intersected
Take the inverse
no fractions
overbar for negative numbers
use parentheses
Polyethylene (Example and repeating unit)
Grocery bags
{C-C} H’s are omitted
Polyvinylchloride (PVC) Example and repeating unit
PVC Pipes
{C-C} H’s are omitted
Cl
Polytetrafluoroethylene (PTFE) Example and repeating unit
Non-stick coatings
F F
C-C
F F
Polypropylene (PP) Example and repeating unit
Cups
C
{C-C} H’s are omitted
Polystyrene (PS) Example and repeating unit
Styrofoam
{C-C} H’s are omitted
l
Benzene Ring
How are HCP and FCC structures different
HCP layers stacked ABA Pattern
FCC Layers stacked in CBA Pattern
Network Former
Connects tetrahedra to 3D network
Introduces Bridging oxygens
Network Modifier
Introduces non bridging oxygens
Breaks up SiO2 network
Two properties that are strongly dependent on atomic bonding
Young’s modulus (expanding and contracting)
Tensile Strength (how much force you can put on material before it breaks)
Isotactic
All R groups on same side of polymer
Syndiotactic
R groups are on alternate sides of polymer
Atactic
R groups are randomly position on polymer
Block copolymer (Example and pattern)
SBR (Tires) AAABBB
Random Copolymer (Example and Pattern)
SBS (Shoe soles) ABBAABBBABAA
Alternating Copolymer (Example and Pattern)
ABABA
Used primarily in academic settings
Graft copolymer (Example and Pattern)
ABS (Legos)
B
B
AAAAA
B
B
Polymer Crystallinity
Regions of well packed oriented atoms
- Lamellae (Chains folded back and forth)
Amorphous regions
- Tie molecules
Spherulite Grown from nucleation site
Step growth
Reactive side groups on two different monomers, causes chains to link up
Chain growth Steps
Initiation
- Adds catalyst/initiator
Propagation
- Chain grows via unpaired e- at active sites
Termination
- Stops growing
Bridging Oxygen
an oxygen atom in a crystal structure or molecule that connects two adjacent atoms, typically silicon atoms, within a network of bonded atoms. In silicate minerals, a bridging oxygen is an oxygen atom that is shared by two silica tetrahedra (SiO₄ units). This connection occurs when one oxygen atom forms covalent bonds with the silicon atoms of two neighboring tetrahedra, linking them together.
Borosilicate Glass
SiO2 and B2O3 network formers
Pyrex (Low thermal expansion coefficient) prevents cracking
- Lab glassware (chemical resistance)
Sodalime Silicate Glass
SiO2 network formers
Na2O & CaO network modifiers
-Windows
Silica Tetrahedron
a basic structural unit of silicate minerals, consisting of one silicon atom surrounded by four oxygen atoms, forming the shape of a tetrahedron. In this structure, the silicon atom is located in the center, and the oxygen atoms occupy the four corners of the tetrahedron. Each oxygen atom is covalently bonded to the central silicon atom.
Non-bridging Oxygen
an oxygen atom in a silicate structure that is bonded to only one silicon atom, rather than being shared between two. Unlike a bridging oxygen, which connects two silica tetrahedra (SiO₄ units), a non-bridging oxygen remains attached to only one tetrahedron, leaving the other bonding site typically open or bonded to a different type of ion,
Amorphous
a material or substance that lacks a well-defined, long-range crystalline structure. In an amorphous solid, the atoms or molecules are arranged in a random, disordered manner, unlike in crystalline materials where they are arranged in a regular, repeating pattern.
Crystalline
a material whose atoms or molecules are arranged in a highly ordered, repeating pattern that extends in all three spatial dimensions. This regular arrangement forms a crystal lattice, which gives crystalline materials distinct geometric shapes, such as cubes, hexagons, or other regular forms.
Glass Transition Temperature
the temperature at which an amorphous material, such as glass or certain polymers, transitions from a hard and relatively brittle state into a more rubbery or pliable state. This transition does not involve a phase change like melting; instead, it reflects a change in the mobility of the polymer chains or the structural arrangement of the glass.
Melting Temperature
the specific temperature at which a solid material transitions into a liquid state under atmospheric pressure. At this temperature, the thermal energy provided to the solid overcomes the intermolecular forces holding the particles in a fixed position, allowing them to move freely and change into a liquid form.
Glass
a solid material characterized by its amorphous, non-crystalline structure, meaning that its atoms or molecules are arranged in a random, disordered manner, rather than in a repeating, ordered pattern as found in crystals. This lack of a defined structure gives glass unique properties, such as transparency, brittleness, and the ability to soften gradually when heated rather than melting at a specific temperature.
Network Former (Google)
elements or compounds in a glass or ceramic material that create the backbone of a three-dimensional network structure by forming strong chemical bonds, typically through covalent bonding. These elements, often oxides, form stable, continuous frameworks by linking together through shared atoms, usually oxygen
Network Modifier (Google)
elements or compounds that, when added to a glass or ceramic material, break up the continuous structure created by network formers. These modifiers do not participate in forming the backbone of the glass network but instead enter the structure and disrupt the connectivity between the network-forming units, such as silica tetrahedra (SiO₄).
Face Centered Cubic
C/A - 1
A:R Relationship - 2*sqrt(2)
APF - .74
Coordination number - 12
(45-45-90 Triangle)
Body Centered Cubic
C/A - 1
A:R Relationship - (4*R)/(sqrt(3)
APF - .68
Coordination number - 8
(30-60-90 triangle)
Simple Cubic
C/A - 1
A:R Relationship - 2R
APF - .52
Coordination number - 6
Hexagonal close packed
C/A - 1.633
A:R Relationship - 2R
APF - .74
Coordination number - 12
Cesium Chloride
Description: 4 Corners + 1 in middle
Formula Unit Type: AX
Range of (Rc/Ra): 0.732-1
Coordination Number (not like atoms): 8
Number of formula units per cell: 1
Iconic
Rock Salt
Description:
Formula Unit Type: AX
Range of (Rc/Ra): 0.414-0.732
Coordination Number (not like atoms): 6
Number of formula units per cell: 4
Iconic
Zinc Blend
Description: 5 top and bottom, 4 in middle layer on center of each face, more in middle
Formula Unit Type: AX
Range of (Rc/Ra): 0.225-0.414
Coordination Number (not like atoms): 4
Number of formula units per cell: 4
Covalent
Fluorite Structure
Description: 9 of same atoms 3 layers, more differing elements in center
Formula Unit Type: AX2
Range of (Rc/Ra): 0.414-0.732
Coordination Number (not like atoms): Ca 2+ = 8
F - = 4
Number of formula units per cell: 4
Ionic
