I got stuck with the following: According to Markus Kohm (Koma-script) one can declare a new command for sub-scribing chemical formula such as H_2 by declaring a new command \Molek \newcommand*{\Molek}[2]{#1\texstsubscript{#2}} which I did by putting this in the preamble of my Koma-book document. In the text I write in an ERT-box \Molek H{2} but get 'Undefined control sequence' \Molek H{2}
Same error, if I put only \Molek in ERT and H{2} afterward. I use koma(book) for my LyX document. Can somebody give me some help? Wolfgang