The formula of sodium thiosulphate is?

The inorganic chemical sodium thiosulfate has the formula ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3\times {\mathrm{H}}_2\mathrm{O}$. Usually, it can be found as the pentahydrate ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3\cdot 5{\mathrm{H}}_2\mathrm{O},$ which is white or colourless. The solid is a well-dissolving efflorescent crystalline material.