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