Coord. Compound Homework: Mercury (II), Sulfate, Potassium, Ba(NO3)2

[XTEND]

Homework Statement

A coord. compound of mercury (II) is found to contain the sulfate ion and the potassium ion as well as Hg+2. Ba(NO3)2 solution is added to a water solution of this compound, but there is no precipitate. If the coord. # is 4, and a H20 solution of the compound shows an electrical conductivity equal to 7 ions per formula unit, what is the formula?

Homework Equations

N/A

The Attempt at a Solution

[Hg(SO4)4]K2

not sure ?

 

[kldickson]

The sulfate ion isn't a ligand.

 

[Fightfish]

Are you sure its a sulfate and not a sulfite ion? Cos' like kldickson mentioned, the sulfate ion isn't a ligand, yet there are no free sulfate ions since no ppt is formed with barium nitrate. Also, the species that you mentioned there is not a compound - it has a net negative charge.

 

[XTEND]

ya it must be SO3

But what about the name of the compound? I must be way off?

 

[Fightfish]

Then its probably K6 [Ag(SO3)4], though i have doubts about the feasibility of its formation. Not sure about the nomenclature of sulfite ligands and the "anionic complex-ed" mercury

 

[kldickson]

Set up a reaction between the barium nitrate and the mercury-potassium-sulfate solution.

Also, if I am correct, anions typically aren't ligands.

 

[Fightfish]

Also, if I am correct, anions typically aren't ligands.

Not true, anions are in fact rather common ligands since they are stronger ligands than water. For instance, some common ligands are Cl- and CN-.

 

[kldickson]

Fightfish, you're right about the anions.

 

[Borek]

The sulfate ion isn't a ligand.

Not particullarly efficient at complexing, nonetheless some of its complexes have overall stability constants in the 10⁴ range.

Mercury SO₃^2- complexes are much much more stable.

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