How to draw uranyl cation with lone pair regions and cation charge?

I would like to draw the cation uranyl. So far this is what I have

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

\chemfig{
O~U~O
}
\end{document}


And that produces the following image:

However I would like to get something like this (sorry for my poor artistic abilities).

Is the only way to use tikz? My problem is that I do not how to draw the desired diagram using chemfig.

It is rather straightforward with plain TikZ but also not too difficult with chemfig, which is of course based on TikZ.

\documentclass[margin=3.14mm]{standalone}
\usepackage{chemfig}
\usetikzlibrary{decorations.markings,positioning}
\tikzset{triple line with arrow/.style args={#1,#2,#3}{decorate,decoration={markings,%
mark=at position 0 with {\coordinate (ta-base-1) at (0,2pt);
\coordinate (ta-base-2) at (0,0pt);
\coordinate (ta-base-3) at (0,-2pt);},
mark=at position 1 with {\draw[#1] (ta-base-1) -- (0,2pt);
\draw[#2] (ta-base-2) -- (0,0pt);
\draw[#3] (ta-base-3) -- (0,-2pt);}}}}
\begin{document}
$\left[~~\vcenter{\hbox{% \schemestart \chemfig{ @{O1}O-[,,,,triple line with arrow={-,-,->}]U-[,,,,triple line with arrow={<-,-,-}]@{O2}O } \schemestop \chemmove{ \draw[-] (O1) to[out=150,in=-150,looseness=4] (O1); \node[left=-3pt of O1.west,font=\small\bfseries]{:}; \draw[-] (O2) to[out=30,in=-30,looseness=4] (O2); \node[right=-3pt of O2.east,font=\small\bfseries]{:};}}}~~ \right]^{2+}$
\end{document}


Of course, you can adjust the arrow style as you like, e.g. -latex instead of ->.