Question

ionic compounds form
crystal structures.
molecular structures.
pure elements.
neutral elements.

Explanation:

Ionic compounds are composed of ions held together by ionic bonds. In the solid state, these ions are arranged in a regular, repeating three - dimensional pattern known as a crystal lattice or crystal structure. Molecular structures are characteristic of covalent compounds where molecules are formed. Pure elements are substances made up of only one type of atom, and ionic compounds are made up of at least two different types of ions (from different elements). The term "neutral elements" is not a correct description for the structure of ionic compounds. So ionic compounds form crystal structures.

Answer:

A. crystal structures.