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Two novel definitions of chemical coordination numbers – valence entropy coordination number nVECN and valence diversity coordination number nVDCN – are proposed. Their originality stems from the fact that they are the first definitions based solely on bond valences. The expressions for them are derived from their definitions and their properties are studied. The unexpected close relationship of nVECN to Shannon entropy and nVDCN to diversity are revealed and the names of the new coordination numbers are taken therefrom. Finally, as an example, a study of arsenic(III) lone electron pair stereoactivity with respect to AsIII coordination number is carried out to demonstrate the usefulness and advantages of the new definitions as well as to compare them with the existing ones.

Supporting information


Text file
Code for the functions to compute nVDCN, nVECN and nECoN with the LibreOffice Calc Spreadsheet.


Portable Document Format (PDF) file
Figs S1, S2, S3, S4, Tables S1, S2 and Section S1

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