[sb]

If 'd' is the ratio of the total number of electrons in a compound and the average radius(of all anions and cations, or covalent radii), are there known compounds (inorganic or organic) where d is high?

Are there any rules or analytic techniques to design such compounds that have stable chemistry?

Don't confuse the electron density in the title to https://en.wikipedia.org/wiki/Electron_density

[Corribus]

It would mostly be determined by the atomic weight of the atoms involved. Most electrons don't participate in bonding.