I'm using chemfig to draw chemical figures. However, when drawing double bonds as side group onto a carbon chain, I get a little gap. This behaviour is different e.g. in chemdraw, where it looks better in my opinion.
This is my mwe:
\documentclass[border=2pt]{standalone}
\usepackage{chemfig}
\usepackage{mathpazo}
\renewcommand*{\familydefault}{\sfdefault}
\renewcommand*{\printatom}[1]{\ensuremath{\mathsf{#1}}}
\setdoublesep{0.35700 em} % 'Bond Spacing'
\setatomsep{1.478500 em} % 'Fixed Length'
\setbondoffset{0.18265 em} % 'Margin Width'
\setbondstyle{line width = 0.06642 em}
\setbondstyle{thick,cap=round}
\begin{document}
\chemfig{
-[:30](=[2]O)-[:-30]
}
\end{document}
How can I remove this gap and "attach" the boule-bond onto the backbone? Drawing Carbon-Atoms is not the desired solution in this case.