Sodium hexachloroplatinate(IV), the

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

chloroplatinic acid Chloroplatinic acid (also known as hexachloroplatinic acid) is an inorganic compound with the formula 3Osub>2 tCl6H2O)''x'' (0 ≤ ''x'' ≤ 6). A red solid, it is an important commercial source of platinum, usually as an aqueous solution. Alth ...

, is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

with the formula Na₂ tCl₆'', consisting of the sodium

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

and the hexachloroplatinate

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

. As explained by Cox and Peters, anhydrous sodium hexachloroplatinate, which is yellow, tends to form the orange hexahydrate upon storage in humid air. The latter can be dehydrated upon heating at 110 °C. The compound is utilised as the most common chemical shift reference in platinum-195 NMR spectroscopy, relative to which the shifts of other platinum species in solution are reported.

Preparation and reactions

Sodium hexachloroplatinate is obtained as an intermediate in the preparation of Pt complexes, often starting with the dissolution of platinum in aqua regia, giving hexachloroplatinic acid, which is then reacted with

sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...

and evaporated, leaving the salt behind. :Pt + 4 HNO₃ + 6 HCl → H₂ tCl₆+ 4 NO₂ + 4 H₂O :H₂ tCl₆+ NaCl → Na₂ tCl₆+ 2 HCl The compound can be converted back to platinum metal via conversion to the ammonium salt followed by thermal decomposition, allowing platinum metal to be recovered from laboratory residues. :Na₂ tCl₆+ 2 NH₄Cl → (NH₄)₂ tCl₆+ 2 NaCl :3 (NH₄)₂ tCl₆→ 3 Pt + 2 N₂ + 2 NH₄Cl + 16 HCl This compound also reacts with a base, such as

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali ...

, producing t(OH)₆sup>−2 ion.

Applications

A 1.2 M solution of sodium hexachloroplatinate in D₂O is the most commonly chosen reference compound for chemical shifts in ¹⁹⁵Pt NMR. The salt is chosen as it is commercially available at a lower price relative to other platinum compounds, and it possesses high

solubility In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubil ...

enabling quick acquisition of spectra.

References

Platinum(IV) compounds Sodium compounds Chloro complexes Hexachloroplatinates {{inorganic-compound-stub