What is the structural formula of calcium propanoate?

1 Answer
Jul 29, 2015

The formula of calcium propanoate is ("CH"_3"CH"_2COO)_2"Ca"#.

Explanation:

You can tell from the name that this is the calcium salt of propanoic acid.

The formula of propanoic acid is #"CH"_3"CH"_2"COOH"#, so the propanoate ion is #"CH"_3"CH"_2"COO"^(-).#

Calcium is in Group 2, so calcium ion is #"Ca"^(2+)#.

It takes two propanoate ions to balance the charge of one calcium ion, so the formula of calcium propanoate is #("CH"_3"CH"_2"COO")_2"Ca"#.

Note the exception: The salts of carboxylic acids usually have the metal ion written last.

#"Ca"("CH"_3"CH"_2"COO")_2# is acceptable, but #("CH"_3"CH"_2"COO")_2"Ca"# is preferred.