All Questions
7 questions
8
votes
2
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2k
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Why are there only 14 types of Bravais lattices and not 28 when there are 7 types of unit cells and each can have four variations?
As the title suggests, I can't understand why certain kinds of variations (like Face-centred or Body-centred) are restricted to certain types of unit cells. An orthorhombic unit cell has Primitive, ...
- 337
1
vote
0
answers
37
views
HCP and hexagonal primitive cell [duplicate]
There are 14 types of Bravais lattices one of them is hexagonal which is just present as primitive cell ie the basis are at its corners , now when I read about hexagonal closed packing I came to know ...
- 29
2
votes
2
answers
2k
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Conventional unit cell for a hexagonal crystal system
The figure shows a unit cell of a hexagonal crystal system. Drawn in bold, is the unit cell. The lightly shaded one is a unit cell as well and has a six fold symmetry along an axis, hence is more ...
- 313
1
vote
1
answer
2k
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How do I find miller indices for a plane whose intercepts are fractions of the lattice constant?
[I'm talking with respect to cubic lattices alone.]
For instance, if a plane has $x,y,z$ intercepts $a/2,a/2,a/2$ (where $a$ is the lattice constant) the miller index would be $[2\space2\space2]$. The ...
- 113
4
votes
2
answers
929
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Is there a standard scholarly reference for lattice constants of crystals of the elements?
I need to discuss the lattice constants of bulk crystals of several metal and semiconductor elements. I can find plenty of tables and numbers that are probably "close enough" but for a paper ...
- 5,997
5
votes
1
answer
3k
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How do the three Miller indices (hkl) denote planes orthogonal to the reciprocal lattice vector?
The Wikipedia page for Miller indices defines Miller indices as follows:
There are two equivalent ways to define the meaning of the Miller indices: via a point in the reciprocal lattice, or as the ...
- 1,103
3
votes
1
answer
185
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Does a molecule need to be placed symmetrically in the unit cell?
I was watching an OCW by MIT (3.091X) on solid state. My previous notion of lattice point and unit cell got shattered after this example.
Where are the unit cell and lattice points in this picture?
...
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