Face-Centered Cubic

Definition

Face-Centered Cubic (FCC) is a type of crystal lattice structure in which atoms are arranged in a three-dimensional grid, with an atom located at each corner of the cube and an additional atom at the center of each face of the cube. This arrangement is one of the fundamental lattice structures observed in crystalline solids.

5 Must Know Facts For Your Next Test

1. The face-centered cubic (FCC) crystal structure has a coordination number of 12, meaning each atom is surrounded by 12 nearest neighbor atoms.
2. Metals such as copper, gold, silver, and aluminum commonly crystallize in the FCC structure.
3. The FCC unit cell contains a total of 4 atoms: one at each of the 8 corners and one at the center of each of the 6 faces.
4. The FCC structure has a high atomic packing factor of approximately 0.74, indicating that the atoms are closely packed together.
5. The FCC structure exhibits high symmetry, with 48 symmetry operations, making it one of the most common and stable crystal structures observed in nature.

Review Questions

• Describe the key features of the face-centered cubic (FCC) crystal structure.
  • The face-centered cubic (FCC) crystal structure is characterized by a three-dimensional arrangement of atoms, with an atom located at each corner of the cube and an additional atom at the center of each face. This arrangement results in a high coordination number of 12, meaning each atom is surrounded by 12 nearest neighbor atoms. The FCC unit cell contains a total of 4 atoms, and the structure exhibits high symmetry with 48 symmetry operations. Metals such as copper, gold, silver, and aluminum commonly crystallize in the FCC structure, which has a high atomic packing factor of approximately 0.74, indicating a closely packed arrangement of atoms.
• Explain the relationship between the face-centered cubic (FCC) crystal structure and the concept of a unit cell.
  • The face-centered cubic (FCC) crystal structure is defined by the arrangement of atoms within the unit cell, which is the smallest repeating unit that, when stacked, forms the entire crystal structure. In the FCC unit cell, there are a total of 4 atoms: one at each of the 8 corners and one at the center of each of the 6 faces. This specific arrangement of atoms within the unit cell gives rise to the characteristic features of the FCC structure, such as the high coordination number, symmetry, and atomic packing factor. Understanding the unit cell is crucial for comprehending the overall crystal structure and the properties of materials that exhibit the FCC lattice arrangement.
• Analyze the significance of the face-centered cubic (FCC) crystal structure in the context of the solid state of matter and the properties of crystalline solids.
  • The face-centered cubic (FCC) crystal structure is of great importance in the study of the solid state of matter and the properties of crystalline solids. The FCC arrangement, with its high coordination number, symmetry, and atomic packing factor, contributes to the stability and characteristic properties of materials that adopt this structure. For example, metals like copper, gold, and aluminum, which have the FCC structure, exhibit high electrical and thermal conductivity, ductility, and resistance to corrosion. These properties are directly related to the efficient packing and arrangement of atoms within the FCC lattice. Understanding the FCC structure is crucial for predicting and explaining the behavior of materials in the solid state, as well as for designing and engineering new materials with desired properties.

Related terms

Crystal Lattice: A regular, three-dimensional arrangement of atoms or molecules in a crystalline solid.

Unit Cell: The smallest repeating unit that, when stacked, forms the entire crystal structure.

Coordination Number: The number of nearest neighbors or atoms that surround a given atom in a crystal structure.