[Luna101]

Hi please help me sketch the unit cell, determine the lattice shape and the number of “atoms” in the unit cell in the picture. Thanks in advance!

[Babcock_Hall]

Would you show us your attempts?  A good place to start is by defining what a unit cell is.

[Luna101]

I did the regular shapes like cube, Triangles and rectangle but the patterns I don't know where to start

[Babcock_Hall]

Start with the definition of a unit cell, and apply it to each example.  In problems such as these there is typically more than one right answer.

[Luna101]

Ok can you please show me at least an example from the patterns??

[AWK]

You have to find unit cells of two-dimensional space groups (or the bases of parallelepipeds of three-dimensional groups)
The base of a unit cell can be as small as possible a square, rectangle, rhombus, or parallelogram. It is often possible to select another cell with the same area (two-dimensional).
Search your crystallography textbook for plane symmetry group (s) or Wikipedia for Wallpaper group (very complex explanation).

[Luna101]

Please please just do one example from the picture so I can refer to it when I do the other problems please

[AWK]

Look at the layer of the NaCl structure closest to you. Does that remind you of anything?

[Luna101]

Is is supposed to represent pattern #2 or #4?

[AWK]

Patern 2 has identical elements!

[Luna101]

Oh ok thanks. I figure out pattern 3 and 4 but I’m not sure about pattern 1,5,6

[Luna101]

Never mind I figured it out