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Introduction to crystallography: finale Flashcards | StudBud
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Introduction to crystallography: finale
Introduction to crystallography: finale
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1
The lattice body-centered orthorhombic. What is the Bravais type of its reciprocal lattice?
Face centered orthorhombic
Primitive orthorhombic
Body centered orthorhombic
Face centered orthorhombic
2
Which of these represent to a
point
symmetry operations?
All of above
4-fold rotoinversion axis
6-fold rotation axis
Inversion
3
Mark the symmetry element that is NOT possible in periodic systems
Inversion
3-fold symmetry axis
7-fold symmetry axis
Mirror plane
4
A cubic crystal (a=10Å) is investigated using powder diffraction (\lambda=1Å). Find the 2\theta of 2 0 0 peak
0 degrees
180 degrees
11 degrees
60 degrees
5
What are the coordinates of "voids" in the case below
\left[\frac{2}{3}\frac{1}{3}\right]
\left[11\right]
\left[00\right]
\left[\frac{1}{2}\frac{1}{2}\right]
6
The correct equation of lattice planes
\left(hx+ky+lz\right)^2=N
hx^2+ky^2+lz^2=N
hx+ky+lz=N
x+y=N
7
How many
3D
crystallographic space groups
do you know?
14
230
32
17
8
You see the image of an X-ray spectrum. Show characteristic lines
2
1
9
The space group is described by the following symmetry operations. Select special position
\left[0.5,0.3\right]
\left[0.2,0.5\right]
\left[0.1,0.1\right]
\left[0,0.9\right]
10
What is an ancient definition of a crystal?
Natural ice
Ruby
Quartz
Diamond
11
What is included in the
official
(according to the IUCr) definition of a
crystal
?
Anisotropy of properties
Natural faces
Long-range order
X-ray diffraction pattern
12
Reduce the position of an atom to the unit cell \left[-2.3,-0.1,7.6\right]
\left[0.3,0.9,0.4\right]
\left[0.7,0.1,0.6\right]
\left[0.7,0.9,0.6\right]
\left[0.3,0.1,0.6\right]
13
What is the path difference between waves
n
and
n+1
?
d
2d
d\sin\theta
2d\sin\theta
14
Recognize
Bravais type
of this lattice
Rectangular simple
Rectangular centered
Square
Oblique
15
What is correct about X-rays?
All of above
Can easily pass through matter
Have similar physical nature as visible light, just different wavelength
Are electromagnetic waves
16
Which properties are relevant for "Wyckoff positions"
Multiplicity (the number of equivalent positions in the unit cell)
Both of above
Local symmetry (local point symemtry group)
17
What is the mathematical reason to introduce reciprocal lattice....
No reason: recipocal lattice is useless
To make student's life more complicated
For aesthetical reasons
To simplify vector operations in non-Cartesian crystal space
18
Laue experiment: \lambda=1Å. The UC volume is 100 Å
3
.
Estimate
the maximum number of Bragg peaks.
3500
35
35000
500
19
What is the term "peak multiplicity"?
Width of Bragg peak
The number of overlapping peaks at given2\theta
Total number of peaks in a powder diffraction pattern
Intensity of Bragg peak
20
What movement is associalted with
4-fold rotoinversion
axis
Rotation by 90\degree
Rotation by 90\degree followed by the inversion
Inversion 4 times
Rotation by 90\degree
21
How many lattice parameters are necessary for a 3D lattice?
6
4
3
2
22
The transformation of coordinate system is drawn below. Describe it mathematically (in algebraic form)
x,y
x+\frac{1}{2},\overline{y}+\frac{1}{2}
\overline{x},\overline{y}
\overline{x}+\frac{1}{2,}y
23
You see the symmetry diagram. Which crystal system does it correspond to?
Tetragonal
Trigonal
Hexagonal
Cubic
24
Select the closest association (according to the lecture) to the term
symmetry operation
Unit cell
Movement
Crystal lattice
Natural ice
25
How many space groups, corresponding to the structures with one atoms per primitive unit cell?
14
32
5
230
26
Which of these objects are
more
symmetrical?
CRYSTALS
GLASSES
27
Name 2D symmetry operation which is given by the algebraic expression \overline{x},\overline{y},z+\frac{1}{2}
Glide plane, c
2-fold screw axis
Translation
Mirror plane
28
Reciprocal lattice is build using the basis vectors
a
i
*. These vectors are related to
a
i
as
ai* are not related to ai
ai*aj =δij
ai*aj = 1
ai*=ai
29
Which numbers can be valid Miller indices of lattice planes
\left(000\right)
none of above
\left(246\right)
\left(1\overline{1}2\right)
30
How many 2D holohedry groups would you expect
4
5
32
14
31
How many of them are from Israel?
1
4
2
0
32
Find the Miller indices of the planes below...
\left(21\right)
\left(\overline{1}2\right)
\left(32\right)
\left(12\right)
33
Two groups belong to the same crystal system. One of them is HOLOHEDRY another is MEROHEDRY. Which has higher order?
HOLOHEDRY
MEROHEDRY
34
X-rays are relfected from (112) planes. The path difference is equal to 4\lambda. Find hkl
448
224
444
112
35
There is ONLY one possible choice of basis vectors of crystal lattice
False
True
36
The term "crystal system" describes...
Number of atoms in a unit cell
Symmetry of a crystal lattice
Chemical composition
Symmetry of a unit cell
37
Which of these objects has
non-crystallographic
symmetry elements
A
F
C
B
D
E
38
How many
Nobel Prizes
are associated with crystallography?
35
20
16
29
39
What defines position of Bragg peaks on the powder diffraction pattern?
Lattice parameters
Orientation of the sample
Type of a detector
Positions of atoms in a unit cell
40
What is the definition of the "group order"?
The number of rotation axes in the group
The number of mirror planes in the group
The number of group generators
Total number of elements in the group
41
The experiment of Max von Laue provided an ultimate proof that...
All of above
X-rays are electromagnetic waves
The structure of crystals is 3D periodic
X-ray wavelength is comparable to lattice parameters...
42
According to R.J. Haüy, what stands behind the natural shapes of crystals
Aesthetics of crystal shapes
Energy conservation law
Periodicity of their structures
God's will
43
The group order is 3. The unit cell contains four symmetry independent atoms. Which of them is at the general position?
4
1
2
3
44
How many 3D crystal systems / Bravais types of lattices do you know?
7 / 230
7 / 32
4 / 5
7 / 14
