How to input latex math equation in scrivener?

I know I can use MathType to input equation, but it is not enough.

Well you can use MultiMarkdown or Pandoc which allow full use of LaTeX maths, and if you use Scrivener 3 you can use Styles to manage them. Screenshot shows styled LaTeX maths which compiles to $$math$$ which is transformed into Maths by Pandoc:

Little question, I’m using scrivener and pandoc (with the amazing Ian’s scrivomatic) and I usually export directly to docx. When it comes to write equation I can use $$ my equation$$ and see it in word as equation, but I don’t understand which syntax is supported.
For example \rightarrow works well for chem reactions, but if I want to write something above the arrow the \xrightarrow(wordabove) is not recognised. I red from pandoc user guide that if you process directly to docx OMML math markup is used. So I tried just things that actually works when used in word equation editor, such as \rect(a/b) to see text in square box. But it doesn’t work when used with scrivener and pandoc. Is it possible to extend the syntax I can use as I can do with latex using additional packages? Do someone know which syntax is usable with pandoc?

Thank you