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Unit cell of hcp structure

It is given in my book that the structure in figure-1 is the unit cell of hcp structure. So why then is the structure in figure-2 not the unit cell as we can repeat the structure in figure-2 to get ...
Asher2211's user avatar
  • 159
6 votes
3 answers
10k views

Converting fractional coordinates into cartesian coordinates for crystallography

So let's say for a given molecule I have the volume of a unit cell, the shape of the unit cell (monoclinic, cubic, etc), the cell angles alpha, beta, and gamma, the cell lengths a,b, and c, and a list ...
crystallography's user avatar
5 votes
0 answers
173 views

How is the Born-Lande equation modified when the structure is not NaCl?

Often the Born-Lande equation is quoted (alongwith the calculation of the Madelung constant and Born exponent) with reference to rock-salt structure. But what if we take some other crystal, like ...
Awe Kumar Jha's user avatar
8 votes
0 answers
4k views

What are the limitations of the Born-Lande' equation?

The Born-Lande' equation is used to theoretically calculate the lattice energy, $\Delta U$, of ionic compounds. It is often cited as such in literature, $$\Delta U = -\frac{k_Az_1z_2Me^2}{4 \pi \...
Prithvi Ramrucha's user avatar
1 vote
0 answers
95 views

Lattice Energy of MX2 type

While finding the solution to the question that which among BaO and BaCl2 has hi that is energy I found that it was BaO whose lattice energy is high and there were explaining it just with charges. So ...
Nick's user avatar
  • 37
3 votes
1 answer
185 views

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? ...
Aditya Shrivastava's user avatar
0 votes
1 answer
60 views

Do two Miller planes need to have similar arrangement of atoms?

For two Miller planes, do I need to have the same arrangement of atoms in both of them? Does it need to look like the same plane translated a little? I have this question because if this is not the ...
Mahathi Vempati's user avatar