Dot between the molecular formula of compounds

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SUMMARY

The discussion clarifies the use of a dot in molecular formulas, such as CuSO4·10H2O and CaCO3·MgCO3, indicating a stoichiometric mixture of compounds. This notation signifies non-covalent associations, commonly seen in hydrates, but also applies to other mineral compositions like MgO·Al2O3 for spinel. The dot does not imply a deeper chemical relationship, as the components can sometimes be separated. Overall, it serves as a concise representation of mixtures in chemistry.

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donaldparida
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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?
 
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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.
 
Generally, it refers to substances non-covalently associated together, such as the case of hydrates.
 
Ygggdrasil said:
substances non-covalently associated together

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.
 
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