Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Dot between the molecular formula of compounds

Tags:
  1. Nov 20, 2016 #1
    I have seen many instances of molecular formulas of two or more compounds with a dot between two adjacent molecular formulas like CuSO4.10H20, CaCO3.MgCO3, K2SO4.Al2(SO4)3.24H20 and so on. What does the dot indicate?
     
  2. jcsd
  3. Nov 20, 2016 #2

    Borek

    User Avatar

    Staff: Mentor

    That the substance can be thought of as if it was a stoichiometric (that is, in a simple, constant ratio) mixture of other substances. Sometimes they can be separated, sometimes they can't, so there is no deeper meaning.
     
  4. Nov 20, 2016 #3

    Ygggdrasil

    User Avatar
    Science Advisor

    Generally, it refers to substances non-covalently associated together, such as the case of hydrates.
     
  5. Nov 20, 2016 #4

    Borek

    User Avatar

    Staff: Mentor

    You are right that's what we usually mean when it comes to hydrates, but the same notation is used also for other situations. Sometimes minerals are written in the oxide form (at least that's how it is called in Polish), like spinel being MgO⋅Al2O3. Also dolomite MgCO3⋅CaCO3 is hardly made of non-covalently associated entities.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Dot between the molecular formula of compounds
  1. Molecular Formulas (Replies: 3)

Loading...