Molecular Mondays: Sodium Carbonate

Just a new "feature" I've been thinking of. I'm kicking it off with something rather mundane, but a bit interesting to me.

You have 2 very closely related compounds: Sodium Carbonate and Sodium Bicarbonate. A modern name for Sodium Bicarbonate is Sodium Hydrogen Carbonate.

So, structurally sodium carbonate looks a bit like this (actually there should be 2 Na⁺ ions):

And Sodium Hydrogen Carbonate is subtly different:

Can you spot the difference?

Sodium carbonate is a stronger base than sodium hydrogen carbonate, and it's all due to the hydrogen tacked to one of the oxygens. Adding another hydrogen makes it an acid:

Which is formed when carbon dioxide is dissolved in water:

Oh, and incidentally, the bi in bicarbonate has to do with the fact that the carbonate ion is attached both to the sodium and hydrogen.