Short answers, pulled from the story.
Gilbert Lewis published a paper in 1916 describing the sulfate ion with electron octets around each atom. He identified two double bonds and assigned a formal charge of negative one to each oxygen atom while the sulfur atom carried a positive charge of plus six.
The measured S-O bond length is 149 picometers which is shorter than the 157 picometer bond found in sulfuric acid. Modern consensus favors four single bonds over the double bond structure despite Pauling attributing this shortness to d orbital involvement.
Lead(II) sulfate and barium sulfate form insoluble precipitates when mixed with solutions containing sulfate ions. Radium sulfate stands out as the most insoluble sulfate known among all metal sulfates.
Copper sulfate functions as a common fungicide in agricultural settings where its stable pentahydrate form creates Bordeaux mixture for crop protection. This compound also serves as an electrolyte in galvanic cells and helps farmers protect crops from fungal infections.
Paul Crutzen detailed a proposal for stratospheric aerosol injection in 2006 after recognizing sulfate importance to global climate. Deploying aerosols in the stratosphere ensures they remain at maximum effectiveness to offset warming under high-emission scenarios like RCP 8.5.