Home > Community > How many 4th nearest neighbours are there in an hcp lattice?
Upvote

VOTE

Downvote
+ Crystallography
+ Chemistry
Posted by
Marko Sokolich

How many 4th nearest neighbours are there in an hcp lattice?

David Filmer  Follow

With HCP, things get hairy pretty quickly.

This is the first coordination sphere, with 12 atoms at the distance $a$ from the origin:

Sphere 1

These are the second nearest neighbors, i.e. the 6 atoms at $\sqrt{2}a$ from the origin, each touching 4 atoms of the first sphere:

Sphere 2

These are the third nearest neighbors, which are the 2 atoms at $\sqrt{8\over3}a$ from the origin, each touching 3 atoms of the first sphere:

Sphere 3

And finally, here are your 18 atoms which are the $4^{th}$ nearest neighbors of the atom at the origin. Each touches 2 atoms of the first sphere:

Sphere 4

More

Upvote

VOTE

Downvote
Ferguson Frankland  Follow
in the chatroom.More
Upvote

VOTE

Downvote
Gregory Smith  Follow
, while the previously added atoms are More
Upvote

VOTE

Downvote
Icy Pisces  Follow
In the figure for second nearest atom, there are 18 atoms linked by the black lines. However, there are only 6 second nearest neighbors. Similarly, in the the figure for 4th nearest neighbors, there are more than 18 atoms linked by the black lines. In the figure for 1st and 3rd nearest neighbors, I can make out the required atoms. Could you please clarify the required neighbor in the 2nd and 4th one.More
Upvote

VOTE

Downvote
Jay Fraser  Follow
shadedMore
Upvote

VOTE

Downvote
Jeff Armstrong  Follow
I found one of the early Olex2 advertising cards mentioned. A small scale photo is More
Upvote

VOTE

Downvote
more replies