# What are options for type-setting high quality Lewis structures?

Textbooks in General Chemistry contain a lot of Lewis dot structures, with different styles (two dots or one line for lone pairs, placement of dots, angle between atoms, leaving out lone pairs, etc.). Here are just a couple examples for a wikimedia search via google:

Some look distorted or unfamiliar while others look "right". Is there a set of standards how to typeset these, or a de facto standard in the form of a software package flexible enough to draw all these?

• Wouldn't this question be suitable for the main site? – Faded Giant Jul 31 at 18:06
• @FadedGiant I am confused. I self-answered about making animated GIFs on the main site and got a comment to move it here. Now I get a comment to move this there ;-) [chemistry.stackexchange.com/questions/137145/] – Karsten Theis Jul 31 at 19:20

Briefly, you can draw virtually any structure with chemfig (given you have enough time). It's a $$\mathrm\LaTeX$$ package by Christian Tellechea (profile at CTAN, profile at TeX.SE). Since it works nicely with another package, TikZ, the aforementioned drawing capabilities can be extended beyond generic chemical formulas. You can also develop your own styles and keep settings within \setchemfig{…} as separate *.sty files and load the one you need.

Specifically for Lewis structures it used to offer specific \lewis macro; these days it's being replaced with \charge macro. I'd prefer not to leave an URL with a hardcoded page number of the manual since it appears that the package undergoes rapid development and things may change in the nearest future.

A linear Lewis dot molecular structure can be drawn by exploiting mhchem in conjunction with \underset{…}{…} and \overset{…}{…} like such:

$$\left[ \ce{ :\!\overset{\Large\cdot\cdot}{\underset{\Large\cdot\cdot}{Cl}}-\overset{\Large\cdot\cdot}{\underset{\Large\cdot\cdot}{O}}\!: } \right]^-$$


$$\left[ \ce{ :\!\overset{\Large\cdot\cdot}{\underset{\Large\cdot\cdot}{Cl}}-\overset{\Large\cdot\cdot}{\underset{\Large\cdot\cdot}{O}}\!: } \right]^-$$

This is by no means a proper reliable method, but so far it seems to work for simple cases.

I had a rather unpleasant experience contributing on Wikipedia's chemistry pages, so I don't do it anymore, but I do know that Wikipedia has a Manual of Style describing how to draw chemical structures.

Unsurprisingly, the top choice there is ChemDraw – for all its faults, when used correctly, it is quite possibly the software that gives the most aesthetically pleasing output. It's of course not free, but the truth is that there's a reason why it's the de facto default for (serious) chemistry publishing.

As a heavy ChemDraw user of several years, I am pretty confident in saying that some of the screenshots you found (such as the carbon monosulfide one) are likely done in ChemDraw.

I say "when used correctly", because the default ChemDraw template is ugly. Please use the ACS Document style or something else that looks better!