CRYSTALLOGRAPHY TRIVIA FINAL ROUND

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CRYSTALLOGRAPHYTRIVIAFINAL ROUND!
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Round 3 Question 1
Twins are said to add another level of symmetry
to a crystal. Why is this?
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Round 3 Question 2

• Which of the following statements about twins are
  true?
• penetration twins form by reflective symmetry
  across a mirror plane
• the composition plane of contact twins
  corresponds to a mirror plane
• polysynthetic twins form from variably oriented
  mirror planes

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Round 3 Question 3
The smallest unit of lattice points that define
the basic ordering of atoms in a mineral is
called what?
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Round 3 Question 4
Which of these 2-D lattice nets is not primitive?
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Round 3 Question 5
Besides translation, what other symmetry element
is possible in 2D lattices that is not present in
point group symmetry of single crystals?
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Round 3 Question 6
These 3D unit cell types are possible in what
crystal class?
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Round 3 Question 7
Screw axes combine what two symmetry operations?
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Round 3 Question 8
Which image is an example of a right-handed screw
axis?
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Round 3 Question 9
The space group - P63/m2/c2/m belongs to what
crystal system?
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Round 3 Question 10
What is the maximum possible number of symmetry
combinations that define 3D lattice arrays?
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Extra Credit Question

• Choose the number of points you wish to wager

What unit cell type and symmetry operations are
present in the space group I41/a2/m2/d and what
crystal system does it belong to?
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Round 3 Question 1
Twins are said to add another level of symmetry
to a crystal. Why is this? Twin symmetry
elements do not usually correspond to crystal
symmetry elements
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Round 3 Question 2

• Which of the following statements about twins are
  true?
• penetration twins form by reflective symmetry
  across a mirror plane
• the composition plane of contact twins
  corresponds to a mirror plane
• polysynthetic twins form from variably oriented
  mirror planes

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Round 3 Question 3
The smallest unit of lattice points that define
the basic ordering of atoms in a mineral is
called what? A Unit Cell
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Round 3 Question 4
Which of these 2-D lattice nets is not primitive?
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Round 3 Question 5
Besides translation, what other symmetry element
is possible in 2D lattices that is not present in
point group symmetry of single crystals? Glide
Lines
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Round 3 Question 6
These 3D unit cell types are possible in what
crystal class?
Orthorhombic
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Round 3 Question 7
Screw axes combine what two symmetry
operations? Rotation and Translation
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Round 3 Question 8
Which image is an example of a right-handed screw
axis?
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Round 3 Question 9
The space group - P63/m2/c2/m belongs to what
crystal system? Hexagonal
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Round 3 Question 10
What is the maximum possible number of symmetry
combinations that define 3D lattice arrays? 230
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Extra Credit Question
What unit cell type and symmetry operations are
present in the space group I41/a2/m2/d and what
crystal system does it belong to? Unit Cell
Body-centered Symmetry Operations 4-fold screw
axis with a perpendicular glide plane with
translation in the a direction 2-fold rotation
axis with a perpendicular mirror plane 2-fold
rotation axis with a perpendicular diamond
glide plane Crystal System Tetragonal
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And the winners are...