Which compound has a covalent macromolecular (giant covalent) structure?

A.     MgO(s)

B.     \({\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}{\text{(s)}}\)

C.     \({{\text{P}}_{\text{4}}}{{\text{O}}_{{\text{10}}}}{\text{(s)}}\)

D.     \({\text{Si}}{{\text{O}}_{\text{2}}}{\text{(s)}}\)

D

One respondent stated that the terminology covalent macromolecular was unfamiliar. All candidates should be familiar with covalent and an alternative to macromolecular is giant which was given in brackets in the question. The question itself was answered correctly by 60% of candidates.