Bicarbonates

[Unknown]

I was just asked a question about bicarbonates that I took for granted
when I learned about them. Namely, why is bicarbonate named bi (meaning
two) carbonate and carbonate (meaning one) named carbonate. According to
the dictionary, the name bicarbonate means having two groups.

A cursory search of the literature only produced the following:

In Modern Inorganic Chemistry (Mellor, J.W.; Longmans, Green and Co., NY
1925), on p 808 "Carbonates contain "CO3" as a dyad radicle (sic). There
are two possible alkali carbonates - normal and acid: (picture deleted).
The
normal salt is formed during the first action of carbon dioxide on sodium
hydroxide: 2 NaOH + CO2 = Na2CO3 + H2O. Sodium bicarbonate ... is formed
when an aqueous solution of the normal carbonate is treated with an
excess of carbon dioxide: Na2CO3 + H2O +CO2 = 2 NaHCO3..."

Could this be the reason for the nomeclature? Specifically, the first
chemist
to discover sodium bicarbonate named it so, because it required two
equivalents of CO2 to make.

Please help me solve this dilemna. I apologize if such a question has
appeared here previously.

Michael Mosher !

[Dave Blackburn]

In article <27a3cb...@owl.csrv.uidaho.edu> (Michael Mosher) writes:
>I was just asked a question about bicarbonates that I took for granted
>when I learned about them. Namely, why is bicarbonate named bi (meaning
>two) carbonate and carbonate (meaning one) named carbonate. According to
>the dictionary, the name bicarbonate means having two groups.
>
>A cursory search of the literature only produced the following:
>
>In Modern Inorganic Chemistry (Mellor, J.W.; Longmans, Green and Co., NY
>1925), on p 808 "Carbonates contain "CO3" as a dyad radicle (sic). There
>are two possible alkali carbonates - normal and acid: (picture deleted).
>The
>normal salt is formed during the first action of carbon dioxide on sodium
>hydroxide: 2 NaOH + CO2 = Na2CO3 + H2O. Sodium bicarbonate ... is formed
>when an aqueous solution of the normal carbonate is treated with an
>excess of carbon dioxide: Na2CO3 + H2O +CO2 = 2 NaHCO3..."
>
>Could this be the reason for the nomeclature? Specifically, the first
>chemist
>to discover sodium bicarbonate named it so, because it required two
>equivalents of CO2 to make.

Not to make but yielded 2 equivalents on acidification (see below)

>
>Please help me solve this dilemna. I apologize if such a question has
>appeared here previously.
>
>
>Michael Mosher !

Consider a carbonate of a +2 ion. You could conceivably have either M(CO3) or
M(HCO3)2. When you dissolve it in water (or react with acid to dissolve &
liberate CO2) you could not see the extra H2O, so you would get either one or
two carbonates. The same nomenclature is used for most dianions where the
second H+ is weakly acidic.

--

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