What is the unit cell and coordinates for wurtzite crystal structure?

In summary, wurtzite is a crystal structure characterized by a stacking sequence of ABABABAB. The unit cell, which is the smallest repetitive unit, specifies the positions of different atoms. However, in the case of wurtzite, only two atoms need to be specified despite the unit cell containing more atoms. This is because the unit cell is obtained by applying symmetrical operations to the asymmetric unit. Additionally, the coordinates (x,y,z) in wurtzite are represented as x*a1, y*a2, z*a3, where a1, a2, and a3 are the unit vectors of the hexagonal lattice.
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As far as I understand wurtzite is the name given to the crystal structure defined by the stacking sequence ABABABAB..
However, I am having a hard time understanding what the unit cell is of wurtzite. From what I know the unit cell is the smallest repetitive unit and in it you specify the position of the different atoms. So I looked up something about wurtzite and found that data:
http://som.web.cmu.edu/structures/S014-ZnO.html
And according to this you only need to specify the position of two atoms, while the unit cells seems to encapsulate a lot more atoms - why are the positions of these not specified?
And another question: The meaning of the coordinates (x,y,z) is x*a1,y*a2,z*a3, where a1,a2,a3 are the unit vectors of the hexagonal lattice - right?
Thanks for taking your time
 
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1. What is the crystal structure of wurtzite?

The crystal structure of wurtzite is a hexagonal close-packed lattice, meaning that the atoms are arranged in a repeating pattern of hexagons with the same number of atoms above and below each hexagon.

2. How is the crystal structure of wurtzite different from other crystal structures?

Unlike other crystal structures, wurtzite has a non-cubic unit cell and is not symmetrical in all three dimensions. It also has a higher packing density compared to other crystal structures like zincblende.

3. What elements make up the crystal structure of wurtzite?

Wurtzite is composed of alternating layers of zinc and sulfur atoms, with each layer offset from the previous one by half of a unit cell. This results in a zinc-to-sulfur ratio of 1:1.

4. What are the properties of wurtzite crystals?

Wurtzite crystals have a high melting point, are brittle and have a hardness of 4.5-5 on the Mohs scale. They also exhibit piezoelectric and pyroelectric properties, making them useful in electronic and optical devices.

5. How is the crystal structure of wurtzite studied?

The crystal structure of wurtzite is typically studied using techniques such as X-ray diffraction, electron diffraction, and scanning electron microscopy. These methods allow scientists to determine the arrangement of atoms and the orientation of crystal planes within the structure.

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