# Quick Miller Index Lattice Problem

1. Feb 11, 2009

### Frinkz

1. The problem statement, all variables and given/known data
Indicate the (111) and ([11]0) ([11] has an over line, so is negative, dont know how to do on forums!) planes in a cubic lattice in a diagram, then calculate the angle between them.

3. The attempt at a solution
I think I have drawn this right (see attatchment), but Im not sure what angle it is refering to.

I would guess it is 90 degrees (in red), but I doubt I would be asked this, maybe the other angle (purple), could someone give any thoughts?

Also if my drawing is wrong, let me know! I wasn't 100% sure about the negative (110)
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

#### Attached Files:

• ###### lattice.jpg
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2. Feb 12, 2009

### nasu

Take the angle between the normals to the planes. It will eliminate ambiguity and it will be much easier. You should know what vector is normal to the plan (h k l) if you studied reciprocal lattice.