Chemistry · Ch 1 — The Solid State
Face-Centred Cubic Unit Cell
Face-Centred Cubic Unit Cell
A face-centred cubic (fcc) unit cell has atoms at all eight corners and also at the centre of each of the six faces. As Fig. 1.15 shows, an atom at a face centre is shared between two adjacent unit cells, so only of it belongs to one cell. Fig. 1.16 shows the cell as (a) an open structure, (b) a space-filling model, and (c) the actual portions of the atoms in one cell.
Counting the contributions:
- 8 corner atoms atom …
What this figure shows. Two adjacent transparent purple/pink cuboidal cells sharing a common face; a single orange/red sphere sits on that shared face, showing 1/2 of the face-centred atom belongs to each of the two cells. …
What this figure shows. Three panels of an fcc cell. (a) 'open structure': black wireframe cube (dashed hidden edges) with small green spheres at the 8 corners and one at the centre of each of the 6 faces.
(b) 'space-filling': cluster of large green spheres.
(c) 'actual portions': cube showing 1/8 corner wedges and 1/2 face spheres of green atoms inside the cube. …