[Tex/LaTex] Draw molecule charge in latex using chemfig

Question

I've got a lewis dot structure diagram as seen in the following image:

However, I would like to have brackets on the outside to indicate the positive charge, since this is supposed to represent H3O 1+. Any suggestions would be appreciated.

Here's my current code:

% Preamble
{\color[rgb]{0.500000,0.500000,0.500000}\documentclass[10pt]{article}
\usepackage[usenames]{color} %used for font color
\usepackage{amssymb} %maths
\usepackage{amsmath} %maths
\usepackage[utf8]{inputenc} %useful to type directly diacritic characters
\usepackage{chemfig}
\newcommand{\pol}[1]{\rlap{${}^{^{\color{red} \delta #1}}$}}
\newcommand{\ind}[0]{\text{ }}}
% ========================= end preamble ============================

\chemfig{\lewis{,H}\pol{+}-\lewis{2:,O}\pol{-}(-[6]\lewis{,H}\pol{+})-\lewis{,H}\pol{+}}

Answer 1

I actually figured this issue out by digging through the 83 pages of the chemfig manual. Here's the code I've changed and the following result:

\chemleft[\chemfig{\lewis{,H}\pol{+}-\lewis{2:,O}\pol{-}(-[6]\lewis{,H}\pol{+})-\lewis{,H}\pol{+}}\ind\ind\chemright]^{+}