Important definition in crystallography

[kelvin490]

Can anyone tell me what's the definition of close packed plane in lattice structure? How can I be sure the close packed plane in FCC structure is (111) ?

 

[Astronuc]

The close packed plane has the smallest (minimum) interatomic spacing.

Compare the atomic spacing of the cube edge (edge of face) with face diagonal and cube diagonal.

This might help - http://www.egr.uri.edu/che/course/che333/Structure.pdf

 

[kelvin490]

The close packed plane has the smallest (minimum) interatomic spacing.

Compare the atomic spacing of the cube edge (edge of face) with face diagonal and cube diagonal.

This might help - http://www.egr.uri.edu/che/course/che333/Structure.pdf

Does it mean a close packing plane is a plane that the atoms cannot be packed any closer?

Thanks for reply.

 

[Astronuc]

Does it mean a close packing plane is a plane that the atoms cannot be packed any closer?

No - it just means that it is the plane with the closest separation of the atoms.

http://www.jwave.vt.edu/crcd/farkas/lectures/structure.ppt

Under normal conditions, the atoms aren't packed closer. Only under increasingly high pressures would they get closer.

 

[alphy]

In crystallography, a close packed plane refers to a plane within a crystal lattice structure that contains the maximum number of atoms or ions packed together in a regular pattern. This type of packing is achieved when atoms are arranged in a way that minimizes empty space and maximizes the number of atoms in contact with each other.

To determine if a close packed plane in a face-centered cubic (FCC) structure is (111), one can use the Miller indices system. In this system, the (111) plane corresponds to a set of parallel planes that intersect the x, y, and z axes at 1/3 of their lengths. This can be confirmed by calculating the Miller indices using the formula (hkl), where h, k, and l represent the intercepts of the plane on the x, y, and z axes, respectively. In the case of the (111) plane in an FCC structure, the Miller indices would be (1,1,1), indicating that the plane intersects all three axes at 1/3 of their lengths.

Another way to verify the close packed plane in an FCC structure is by visual inspection. In an FCC structure, the (111) plane can be identified as a layer of atoms stacked in a triangular pattern, with each atom in contact with six neighboring atoms. This arrangement is characteristic of a close packed plane in an FCC structure.

In summary, a close packed plane in crystallography refers to a plane in a lattice structure with the maximum number of atoms or ions packed together in a regular pattern. The (111) plane in an FCC structure can be determined using the Miller indices system or by visually identifying the triangular arrangement of atoms.