Sodium Chlor-platinate, Na₂PtCl₆

Sodium Chlor-platinate, Na₂PtCl₆.6H₂O, crystallises in red, triclinic prisms, of density 2.499. These become anhydrous at 100° C., being converted into a yellow powder.

The heat of solution of the anhydrous salt is:

[Na₂PtCl₆] + Aq. = Na₂PtCl₆.Aq. +8.54 Cals.

For the hydrated salt:

[Na₂PtCl₆.6H₂O] + Aq. = Na₂PtCl₆.Aq. -10.63 Cals.

The heat of formation is:

[Pt] + 2(Cl₂) + 2[NaCl] = [Na₂PtCl₆] + 73.7 Cals.