What's the plural form of tetrathiafulvalene? Here's the word you're looking for.
Answer
The noun tetrathiafulvalene can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be tetrathiafulvalene.
However, in more specific contexts, the plural form can also be tetrathiafulvalenes e.g. in reference to various types of tetrathiafulvalenes
or a collection of tetrathiafulvalenes.