I think what Eric is referring to is:

#+latex_header: \usepackage[version=3]{mhchem}

@@latex:\ce{^{147}Pm}@@

that exports for me.

\nbsp{}^{147}Pm also seems to work, but might put an extra space in.

you might prefer \phantom{}^{147}Pm

John

-----------------------------------
Professor John Kitchin 
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803

On Mon, May 18, 2015 at 12:09 PM, Eric S Fraga <e.fraga@ucl.ac.uk> wrote:
On Monday, 18 May 2015 at 11:43, Lawrence Bottorff wrote:
> Apparently, chemists cannot do Emacs and/or org-mode when they want to
> prefix the super- bzw. sub-script without a kudge?

I've recently have had to start writing papers with significant amounts
of chemistry in them.  I simply use the mhchem package which supports
all types of chemical notation...  org is quite happy with it for simple
entries although you may need to @@...@@ escape more complex entries.

However, if you wanted something portable, i.e. that could export to
other targets, then this won't help you.  Sorry!
--
: Eric S Fraga (0xFFFCF67D), Emacs 24.4.1, Org release_8.3beta-1136-g0e7062