Chapter 3: The Structure Of Crystalline Solids

Front 1

Crystalline Material

Back 1

Material in which the atoms are situated in a repeating or periodic array over large atomic distances

Front 2

Crystal Structure

Back 2

The manner in which atoms, ions, or molecules are spatially arranged

Front 3

Atomic Hard-Sphere Model

Back 3

Spheres representing nearest-neighbor atoms touch one another

Front 4

Lattice

Back 4

Three-dimensional array of points coinciding with atom positions

Front 5

Unit Cells

Back 5

Subdivision of cystal structure into small repeat entities; basic structural unit or building block of the crystal structure; defines the crystal structure by virtue of its geometry and atom positions within

Front 6

Face-Centered Cubic Crystal Structure (FCC)

Back 6

Unit cell with cubic geometry; atoms located at each of the corners and centers of all cube faces
Copper, aluminum, silver, gold

Front 7

FCC

Back 7

Which structure?
a=2Rsqrt(2)

Front 8

FCC

Back 8

Which structure?
Each corner atom is shared among eight unit cells, whereas a face-centered atom belongs to only two (total of four whole atoms per cell)

Front 9

Coordination number

Back 9

Number of nearest-neighbor or touching atoms

Front 10

12

Back 10

FCC Coordination number

Front 11

Atomic Packing Factor (APF)

Back 11

Sum of sphere volumes of all atoms within a unit cell (assuming the atomic hard-sphere model divided by total unit cell volume
APF = (volume of atoms in a unit cell)/(total unit cell volume)

Front 12

Body-Centered Cubic Crystal Structure

Back 12

Cubic unit cell with atoms located at all eight corners and a single atom at the cube center

Front 13

BCC Equation

Back 13

Which structure?
a=4R/sqrt3

Front 14

BCC Coordination Number

Back 14

8

Front 15

FCC Atomic Packing Factor

Back 15

Which structure?
APF: 0.74

Front 16

BCC Atomic Packing Factor

Back 16

Which Structure?
APF: 0.68

Front 17

Hexagonal Close-Packed Crystal Structure (HCP)

Back 17

Common metallic crystal that has a hexagonal unit cell

Front 18

HCP

Back 18

Top and bottom faces of unit cell consist of six atoms that form regular hexagons and surround a single atom in the center

Front 19

HCP

Back 19

Which structure?
Equivalent of six atoms is contained in each unit cell
1/6 of each of 12 top and bottom face corner atoms, one half of each of the 2 center face atoms, and all 3 midplane interior atoms

Front 20

HCP Dimensions

Back 20

Which structure?
c/a ration: 1.633

Front 21

APF Equation

Back 21

V(S)/V(C)

Front 22

Greek p (roe)

Back 22

Theoretical density

Front 23

A

Back 23

Atomic weight symbol

Front 24

V(C)

Back 24

Volume of the unit cell symbol

Front 25

N(A)

Back 25

Avogadro's Number symbol

Front 26

Equation for density (p)

Back 26

p= nA /[ V(C)*N(A) ]

Front 27

Polymorphism

Back 27

Metals and nonmetals with more than one crystal structure

Front 28

Allotropy

Back 28

Polymorphism in elemental solids

Front 29

Lattice Parameters

Back 29

Unit cell geometry parameters
Three edge lengths, a, b, and c
Three interaxial angles a, B, and y

Front 30

Crystal System

Back 30

Cubic, tetragonal, hexagonal, orthorhombic, rhombohedral, monoclinic, triclinic
Seven combinations of lattice parameters

Front 31

And what do the crystal systems look like?

Back 31

Look at da book muthafuqa

Front 32

Crystallographic Directions

Back 32

Directions of crystals

Front 33

Miller Indices (hkl)

Back 33

Specifies crystallographic planes

Front 34

Linear Density

Back 34

Directional equivalency

Front 35

Planar Density

Back 35

Corresponding parameter for crystallographic planes

Front 36

Linear Density (LD)

Back 36

(number of atoms centered on direction vector)/(length of direction vector)

Front 37

Planar Density (PD)

Back 37

(number of atoms centered on a plane)/(area of plane)

Front 38

PD(110)

Back 38

1/(4R^2*sqrt2)

Front 39

Single Crystal

Back 39

Periodic and repeated arrangement of atoms is perfect or extends throughout entirety of specimen uninterrupted

Front 40

Grains

Back 40

Small crystals

Front 41

Polycrystalline

Back 41

Materials composed of a collection of small crystalls

Front 42

Grain Boundary

Back 42

Atomic mismatch within region where two grains meet

Front 43

Anisotropy

Back 43

Directionality of properties and is associated with variance of atomic or ionic spacing with crystallographic direction

Front 44

Isotropic

Back 44

Substances in which measured properties are independent of the direction of measurement

Front 45

Diffraction

Back 45

Mutual reinforcement of one another; magnitudes of waves interact with each other

Front 46

nL
L=lamda
n = number of wavelenghts
L = diffraction

Back 46

mag = magnitude
SQ(mag) + QT(mag)

Front 47

Bragg's Law

Back 47

nL = SQ(mag)+QT(mag)

Front 48

Magnitude of distance in structures that have cubic symmetry

Back 48

d(hkl)=a/(sqrt(h^2+k^2+l^2))

Front 49

Noncrystalline Solids

Back 49

Solids that lack systematic and regular arrangement of atoms over relatively large atomic distances

Front 50

Amorphous

Back 50

Supercooled liquids (atomic structure resembles that of a liquid); "without form"