From my experience, typically in organic chemistry, the implication of "hetero-atom" in some molecule is understood as B, N, O, S, P or a halogen -- or any nonmetallic element, perhaps.
If one describes a nanostructure that contains inorganic and organic ligands (like metal-organic frameworks), is it safe to describe the metals as heteroatoms? Or should the term be reserved for covalent-type atoms only?
For example, is this an acceptable statement?
Snurr and co-workers showed results for simulated H$_2$ sorption in a variety of rht-MOFs containing only carbon and hydrogen in the linkers, as originally these MOFs did not contain heteroatoms other than oxygen and the metal.