This issue is extremely minor, but the equation on the TeX Meta page is incorrect. Na + Cl yields NaCl and not Na + Cl
You should really, really take a deeper look on the equation! Is it perhaps caused by a bad monitor resolution?
For the equation see especially this answer: https://tex.meta.stackexchange.com/a/649/, though it is not exactly the same – the equation used for the background is actually in the correct form (it’s taken from the TeXample source).