I need to draw the chemical structure of NAD+ (Nicotinamide adenine dinucleotide), My script:

\documentclass[article]{revtex4}
\usepackage{chemfig}
\begin{document}
\chemfig{*6((-H)-((\chemabove{N}{\scriptstyle\oplus}-R))=(-H)-(-(=[:90]O)-[::-60](NH_2))=(-H)-(-H)=)}
\end{document}


The result is quite ugly, the parts on the red circle: atoms are too close to the bonds lines Help, please!

You are using to many parentheses! Your code with just the unecessary parentheses removed (and one ( moved a bit…):

\documentclass{article}
\usepackage{chemfig}
\begin{document}

\chemfig{*6((-H)-\chemabove{N}{\scriptstyle\oplus}(-R)=(-H)-(-(=[:90]O)-[::-60]NH_2)=(-H)-(-H)=)}

\end{document}


Start with the R. To me, it looks nicer without all the Hs:

\documentclass{article}
\usepackage{chemfig}

\begin{document}

\chemfig{[:90]R-\chemabove{N}{\scriptstyle\oplus}*6(=(-H)-(-(=[:90]O)-[::-60]NH_2)=(-H)-(-H)=(-H)-)}

\chemfig{[:90]R-\chemabove{N}{\scriptstyle\oplus}*6(=-(-(=[:90]O)-[::-60]NH_2)=-=-)}

\end{document}


I have to admit that I am quite illiterate in the chemical field ...

This yields:

• Thanks a lot!! You're right about the Hydrogens. But they have to be there. It's for my students... – Patricia Tourón Touceda Feb 5 '18 at 20:19
• That’s what I thought :) – Jasper Habicht Feb 5 '18 at 20:22
• @PatriciaTourónTouceda Just a comment. It is a common practice on the webpage that if you are happy with the answer, you accept the answer, so also other people with similar problem see which answer is correct or you liked. – pisoir Feb 11 '18 at 12:16