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Warren DeLano wrote:

which anyhow usually come with blue and red flipped w.r.t. common sense...

Amen to that!
???
If you make a spacefilling model instead of a surface,
and color the atoms with CPK colors or O colors, acidic
patches have a lot of oxygens and show up red, basic
patches have a lot of N atoms and show up rich in blue.
At neutral pH the acidic patches will be more negative,
and the basic patches more positive.
I can see red being intuitively warmer and blue cooler,
but my common sense doesn't tell me whether red is more
electrically positive or negative, so I rely on the
above mnemonic. Please don't start switching the
assignment around!
(OK come to think of it the positive terminal on
car batteries is usually red, at least for modern
cars with negative ground where positive is the
"hot" terminal, so perhaps there is a precedent for
the opposite convention.)

Happy New Year,
Ed

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