K2SnOH6

K2SnOH6, commonly written as K2[Sn(OH)6], is a potassium salt of the hexahydroxostannate(IV) dianion. In the anion, tin is in the +4 oxidation state and is coordinated by six hydroxide ligands, giving an octahedral [Sn(OH)6]2− core. The solid consists of potassium cations balancing this dianion.

Preparation of K2[Sn(OH)6] is typically achieved by dissolving tin(IV) oxide in hot, concentrated potassium hydroxide to form the hexahydroxostannate(IV) species, which can then crystallize as the potassium salt upon cooling or evaporation. Alternative routes involve ion exchange from solutions containing the [Sn(OH)6]2− anion with potassium ions.

Properties of K2[Sn(OH)6] include its appearance as a white crystalline solid that is highly soluble in water. Aqueous solutions are strongly basic due to the presence of the hexahydroxostannate(IV) anion. The compound is stable under ordinary conditions but decomposes upon strong heating, yielding tin oxide and potassium oxides/hydroxides. In acidic media, the hexahydroxostannate unit is protonated and can revert toward tin oxide species.

Applications of potassium hexahydroxostannate(IV) are mainly in inorganic and materials chemistry. It serves as a source of Sn(IV) in hydroxo-rich aqueous environments and can be used in the preparation of tin oxide films, ceramic formulations, and related tin-containing materials. It also functions as a laboratory reagent for studying tin(IV) hydroxo complexes.

Safety notes: Like many hydroxide-containing salts, K2[Sn(OH)6] is caustic and should be handled with appropriate precautions to avoid skin or eye contact and ingestion. Handle and store away from acids.