Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1...

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1 Symmetry Elements of the 2D Space Groups glide line 2, 3, 4, 6 fold axes Unit cell edge mirror line

Transcript of Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1...

Page 1: Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1 Symmetry Elements of the 2D Space Groups glide line 2, 3, 4, 6 –fold axes Unit

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Symmetry Elements of the 2D Space Groups

glide line2, 3, 4, 6 – fold axes

Unit cell edgemirror line

Page 2: Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1 Symmetry Elements of the 2D Space Groups glide line 2, 3, 4, 6 –fold axes Unit

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Highestorder

rotation

Has reflection?

Yes No

6-fold p6m p6

4-foldHas mirrors at 45°?

p4Yes: p4m No: p4g

3-foldHas rot. centre off mirrors?

p3Yes: p31m No: p3m1

2-fold

Has perpendicular reflections?Has glide reflection?

Yes No

Has rot. centre off mirrors?pmg Yes: pgg No: p2

Yes: cmm No: pmm

noneHas glide axis off mirrors? Has glide reflection?

Yes: cm No: pm Yes: pg No: p1

Page 3: Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1 Symmetry Elements of the 2D Space Groups glide line 2, 3, 4, 6 –fold axes Unit

Find the plane groups in the following 10 patterns marked in the yellow squares (for 1 and 2 the same pattern is shown more than once to help you in seeing/finding the plane group). Draw the unit cell in the each pattern and show the mirror and/or the glide lines accordingly.

Page 4: Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1 Symmetry Elements of the 2D Space Groups glide line 2, 3, 4, 6 –fold axes Unit

1. 1.

Pictures taken by Anke Zurn at Topkapi Palast, Istanbul

p4mm

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2.

Pictures taken by Anke Zurn at Topkapi Palast, Istanbul

No mirrors!

Page 6: Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1 Symmetry Elements of the 2D Space Groups glide line 2, 3, 4, 6 –fold axes Unit

2.

Pictures taken by Anke Zurn at Topkapi Palast, Istanbul

p6 No mirrors!

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kiosk, close to TopkapiPalast;Istanbul, 2009

3.

p6mm

Page 8: Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1 Symmetry Elements of the 2D Space Groups glide line 2, 3, 4, 6 –fold axes Unit

Bamboo basket image source: http://www.fz-juelich.de (modified)

Basket waving: kagome net

4.p6

Page 9: Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1 Symmetry Elements of the 2D Space Groups glide line 2, 3, 4, 6 –fold axes Unit

Kagome network

Page 10: Symmetry Elements of the 2D Space Groupsn.ethz.ch/~nielssi/download/4. Semester/AC II/Uebungen...1 Symmetry Elements of the 2D Space Groups glide line 2, 3, 4, 6 –fold axes Unit

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6.

p4

7.

p4gm

8.

p31m

9.

cmm2

10.

cm