Sodium Hydrosulphide

الوصف

Sodium hydrosulfide is the chemical compound with the formula NaSH. This compound is the product of the half-neutralization of hydrogen sulfide (H2S) with sodium hydroxide (NaOH). NaSH and sodium sulfide are used industrially, often for similar purposes. Solid NaSH is colorless. The solid has an odor of H2S owing to hydrolysis by atmospheric moisture. In contrast with sodium sulfide (Na2S), which is insoluble in organic solvents, NaSH, being a 1:1 electrolyte, is more soluble.
Crystalline NaHS undergoes two phase transitions. At temperatures above **0 K, NaSH adopts the NaCl structure, which implies that the HS− behaves as a spherical anion owing to its rapid rotation, leading to equal occupancy of eight equivalent positions. Below **0 K, a rhombohedral structure forms, and the HS− sweeps out a discoidal shape. Below **4 K, the structure becomes monoclinic. The analogous rubidium and potassium compounds behave similarly.[1]

NaSH has a relatively low melting point of **0 °C. In addition to the aforementioned anhydrous forms, it can be obtained as two different hydrates, NaSH·2H2O and NaSH·3H2O. These three species are all colorless and behave similarly, but not identically. It can be used to precipitate other metal hydrosulfides, by treatment of aqueous solutions of their salts with sodium hydrosulfide. It is analogous to sodium hydroxide, and is a strong base.