crystal structure, unit cell

[rayman]

Can someone please try to help me with this. I have a bcc structure and the question is ''Clearly indicate the unit translation vectors and state their value in Å.

I have attached the sketch :

http://img440.images.../picture3lh.jpg

are those t1,t2,t3 translation vectors?

I know the cell parameters are:[tex] a=b=c=31652\AA[/tex]

Are these correct values of t1,t2,t3 then?

[tex] t_{1}=(-\frac{a}{2},\frac{a}{2},\frac{a}{2})=(-15826,15826,15826)\AA ?[/tex]

and similarly the rest?

And one question more. We need to calculate the volume of the conventional unit cell and volume of the primitive unit cell, is this correct?

[tex] V_{conv}=a^{3}=3171\AA^{3}[/tex]

[tex] V_{primitive}=\frac{V_{conv}}{2}}=1585.5\AA^{3}[/tex]

Is the plane which has the highest degree of compaction (101)??

and the deree of compaction[tex] \frac{\sqrt{2}}{a^2}}[/tex]???

 

It there anything special with a primitive cell? (how would you answer that question)?

[timo]

I have little to no time at the moment but two comments that might help you:

1) t1, ... t3 obviously are translation vectors. The question is whether they are the translations that span a elementary cell. While you can certainly figure that formally by solving some equations, I'd check that visually. To be the vectors you are looking for, a) you have to get to each point to another with an integer multiple of these translations, and b) starting from some point, each integer multiple of these translations must lead you to a new point.

2) The TeX mode in this forum is activated with [ math], not with [ tex].