What is another example of an interstitial compound?

An interstitial compound is formed when smaller atoms occupy the spaces (interstices) between the larger atoms in a metallic lattice. This type of compound typically involves a combination of a metal and a non-metal, where the non-metal atoms fit into the interstitial gaps of the metal structure.

In the case of CuAl2, this compound consists of copper (Cu) and aluminum (Al) and can be classified as an example of an interstitial compound. The aluminum atoms can occupy the interstitial spaces in the copper lattice, leading to enhanced properties such as increased hardness and strength. This characteristic of interstitial compounds makes them useful in various applications, particularly in alloys and hardening processes.

Other options, while they represent different types of compounds, do not illustrate the interstitial characteristics. For instance, SiC is a covalent compound, N2O5 is a molecular compound, and CaSO4 is an ionic compound. Thus, CuAl2 stands out as the correct example of an interstitial compound among the choices provided.