Question

Copper has the face-centered cubic structure. The coordination number of each ion is:
A. ${\text{4}}$
B. ${\text{12}}$
C. ${\text{14}}$
D. ${\text{8}}$

Answer 1

The coordination number for a face-centered cubic structure is the number of nearest-neighbor atoms or ions surrounding an atom or ion in that structure. Hence in order to solve these types of questions, one can understand the face-centered cubic structure of copper and find out the coordination number.

Complete step by step answer:
-First of all let's understand the concept of the face-centered cubic structure. The face-centered cubic structure has lattice points present on the faces of the cube where each gives exactly one-half contribution in addition to the corner lattice points which gives a total of ${\text{4}}$ lattice points which are present per unit cell.
-Each sphere that is present in the face-centered cubic structure lattice has a coordination number ${\text{12}}$ where the coordination number is the number of nearest neighbors of a central atom in the structure.
-The copper ion shows the structural arrangement of a face-centered cubic structure which has the coordination number ${\text{12}}$.
-Therefore, The coordination number of each ion is ${\text{12}}$ which shows option B as a correct choice of answer.

Note: The face-centered cubic structure has a total of ${\text{4}}$ lattice points which are present per unit cell in which $(1/8) \times 8$ comes ​from the corners plus $(1/2) \times 6$ comes from the faces of the lattice. The face-centered cubic system is closely related to the hexagonal close-packed (hcp) system in which the two systems are different from each other only in the relative placement of their hexagonal layers. The face-centered cubic structure is also called the cubic-close packed lattice.