Chemical Forums
Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: gavindor on October 05, 2023, 01:21:57 AM
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I know that a formula unit is what ionic compounds have. (i.e. ionic compounds being not composed of molecules). And I know that the term empirical formula can apply to molecular formulae or to formula units.
Is Formula Unit usually an empirical formula but not always an empirical formula?
e.g. common examples are ionic compounds NaCl and CaCO3 but from what I understand there are also examples of ionic compounds whose formula unit is not an empirical formula , i.e. the ratio of atoms in the formula are not in their simplest form , for example Hg2N2O6 https://pubchem.ncbi.nlm.nih.gov/compound/129646128 or K2S2O8 https://en.wikipedia.org/wiki/Potassium_persulfate Their empirical formulae would be HgNO3 and KSO4 respectively.
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Can KSO4 exist? No some bonding missing. HgNO3 theroretical can exist. But mercury-I connect two Hg in there molecules. So it would be Hg2(NO3)2 or Hg2N2O6
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Is Formula Unit usually an empirical formula but not always an empirical formula?
Yes.
Also Hg2Cl2.
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Can KSO4 exist? No some bonding missing. HgNO3 theroretical can exist. But mercury-I connect two Hg in there molecules. So it would be Hg2(NO3)2 or Hg2N2O6
KSO4 and HgNO3 are empirical formulae. So I think they don't have to exist?
The Formula Units exist Hg2N2O6 and K2S2O8
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That is what I am saying.