Chemical notation: charge and #atoms directly above each other: how?

[nielsgeode]

I'm formatting my PhD dissertation and one of the problems I'm facing is that when I use an equation in the text to format ions (e.g. BH4 -), I get the format correct: the 4 and the negative sign directly above each other, but I cannot change the default font (which is Cambria Math) to match with the rest of my text.



Since the final font and/or layout may still change I prefer a solution where I can just select all text and change the font of the entire thesis at once (if necessary). A solution with images inserted into the text is too impractical, since I have a lot of these notations in my thesis. In addition, it renders this (piece of) text unsearchable in the final PDF.

Any help is greatly appreciated!

Niels