General Description
White or off-white crystalline solid or powder. Mp 1127°C, Sublimes: 1800-1900°C, density: 6.95 g cm-3. Insoluble in water. Soluble in concentrated sulfuric acid, hydrochloric acid. Occurs in nature as the mineral cassiterite. Used as a catalyst, in putty, as a polishing powder for steel and glass, in ceramic glazes and colors. Flowers of tin refers to the material collected as the result of condensation after sublimation.
Reactivity Profile
TIN(IV) OXIDE is non-flammable and non-combustible. Reacts vigorously with strong reducing agents. Incompatible with chlorine trifluoride.
Chemical Properties
white or off-white powder
Physical properties
White or grayish powder; tetragonal crystals; density 6.85 g/cm3; refractive index 2.006; Mohs hardness 6.5; melts at 1,630°C; insoluble in water; soluble in hot concentrated alkalies.
Uses
Polishing glass and metals; manufacture of milk-colored, ruby and alabaster glass, enamels, pottery, putty; mordant in printing and dyeing fabrics; in fingernail polishes.
Uses
Stannic oxide (SnO2) is a whitish powder used as a ceramic glaze and polishing agent.
Definition
ChEBI: Tin dioxide is a tin oxide compound consisting of tin(IV) covalently bound to two oxygen atoms.
Preparation
Tin(II) oxide is prepared by heating tin(II) hydroxide. The latter is obtained as a white precipitate by reacting Sn2+ ions with hydroxide ions: Sn2+(aq) + 2OHˉ(aq) → Sn(OH)2 (s) Sn(OH)2 ?→ ?? SnO(s) + H2O(g).
Purification Methods
Reflux it repeatedly with fresh HCl until the acid shows no tinge of yellow. The oxide is then dried at 110o.
