Today we test the clickers again

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Today we test the clickers again
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We now venture into the world of

• Metals

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Metallic xl Structures

• Face-Centered Cubic (FCC)
• Body-Centered Cubic (BCC)
• Hexagonal Close-Packed (HCP)

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FCC Atoms at 8 corners 6 faces Equivalent of
? whole atoms. Atomic Packing Factor (APF)
.74
Fig. 3.1
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FCC Cubic structure

• STM of Platinum

Dept. Kings.edu/chemlab, Property of IBM
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Whats an STM image?

• A scanning tunneling microscope (STM) is an
  instrument for imaging surfaces at the atomic
  level.

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Atoms.

• You are under our control!

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• 1990 IBM scientist Don Eigler used an STM to
  move single xenon atoms on a nickel surface

• The engineers moved 35 atoms to spell out "IBM"
  in a 10 micrometer logo.

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FCC examples
Lab-grown copper (SEM)
Etched Aluminum (SEM)
Gold
Galena (Pb ore)
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Whats an SEM image?

• A scanning electron microscope (SEM) produces
  images by scanning a sample with a focused beam
  of electrons. Yields topography and composition.

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f02_03_pg42
BCC
Atoms at 8 corners 1 in center of
cube Equivalent of ? whole atoms APF .68
Fig. 3.2
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BCC Cubic structure

• STM of Aluminum (100) surface

https//wiki.fysik.dtu.dk/dacapo/Examples
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BCC examples
Molybdenum
Iron
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• HexagonalSystem
• a1 a2 a3 ? z
• 90º
• g 120º

Fig. 3.7
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f03_03_pg43
HCP
Atoms at 12 corners, 3 in interior, 2 centered
on basal planes Equivalent of ? whole
atoms (APF) .74
Fig. 3.3
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Hexagonal structure

• STM of Nickel surface structure.

Dept. Kings.edu/chemlab, Property of IBM
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Hexagonal structure

• Zinc hand sample

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Hexagonal structure

• SEM of Fine Cadmium powder

SEM of ZnO nanowires http//www.lac.tu-clausthal.d
e/en/arbeitsgruppen/angewandte-photonik-lac/projek
te/zinc-oxide-nanowires-for-photonic-applications/
http//www.sciencephoto.com/media/8998/enlarge
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HCP Examples
Cadmium crystal bar
Titanium crystals
Magnesium (SEM)
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Atomic Packing Factors

• BCC 0.68 FCC 0.74 HCP 0.74

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Metallic xl Structures

• Body-Centered Cubic (BCC) APF 0.68
• Na, Fe, Cr, Mo, W
• Face-Centered Cubic (FCC) APF 0.74
• Cu, Al, Ag, Au, Pb, Ni, Pt
• Hexagonal Close-Packed (HCP) APF 0.74
• Ti, Zn, Cd, Co, Mg

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Crystallographic Directions
Section 3.9
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Crystallographic direction

• A vector between two points in a crystal.
• Example

z
y
x
Unit cube
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And I should know this because.
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Helps us communicate about crystals no matter
where we are in the world
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A systematic study of symmetric tilt-boundaries
in hard-sphere f.c.c. crystals Abstract A new
method is developed for the search of
mechanically stable configurations of symmetric
tilt boundaries in hard sphere f.c.c. crystals.
The problem of finding out relative displacements
which minimize the total volume of two crystal
blocks forming a boundary, is simplified to a
problem of positioning a single atom sphere
relative to a block which consists of real and
image atoms the latter are placed in such a
way to reflect the arrangement in the other
crystal block. The method (the image atom method)
has been applied to the analysis of symmetric
coincidence boundaries with 100, 110 and
111 tilt axes with ?-values 3103. For the
100 (013)?5 boundary, the procedure of the
analysis is described in detail the derived
structures are compared with those by computer
simulation. Numerical data are given in tabulated
forms for some boundaries.
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Steps for finding Crystallographic Directions
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Examples
1
2
y
4
3
y
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Family of Directions

• In the same family
• Vector 1
• Vector 2

z
y
x
Unit cube
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Family of Directions lt1 1 0gt
z

1 1 1 0 2 3 1 1 0 4 1 1 0 5 1 1
0
4
3
y
2
1
5
Unit cube
x
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p_pg44
Family of Directions lt1 1 0gt

• Structurally equivalent
• Atomic packing is equivalent

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p_pg44
Family of Directions lt1 1 0gt

• Structurally equivalent
• Atomic packing is equivalent

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Hexagonal Crystallographic directions

• a1 a2 a3 z
• Vector
• 1 0 0 1

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Other Directions
1 1 0
1 0 2
1 0 1
1 1 1
2 1 1
0 0 1
2 1 1
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WednesdayClicker Questions will include
finding Crystallographic Planes and
Crystallographic DirectionsSolved Examples
posted on Canvas
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Section 3.10 Crystallographic Planes
Miller Indices
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Steps for finding Crystallographic Planes
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Examples
1
2
3
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Families of Planes
100
010
001

(010)
(001)
(100)
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Family of Planes MI (X Y Z)
Structurally equivalent planes X Y Z
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Hexagonal Crystallographic planesThe basal plane
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Other Planes
(0 0 1)
(0 1 1)
(1 1 2)
(1 0 1)
(2 0 1)
( 1 2 3)
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Notation Summary
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Solved Examples posted on Canvas
FilesgtAssignments, Homework, Extra Credit