Sodium Hydrosulfide is an inorganic compound with the formula NaHS. It is colorless needle-like crystal and easily deliquesced. It is soluble in water and alcohols. Crystalline NaHS exists in two phase transitions. At temperatures above 360 K, NaHS assumes the NaCl structure, which implies that the HS− behaves as a spherical anion due to its rapid rotation leading to equal occupancy of eight equivalent positions. Below 360 K, a rhombohedral structure forms, and the HS− sweeps out a discoidal shape. Below 114 K, the structure becomes monoclinic.
It is produced by the reaction of sodium hydroxide and hydrogen sulfide.
NaOH + H2S → NaHS + H2O
It is used as a make-up chemical in the manufacture of paper by Kraft process and to prepare synthetic cooking liquor. It may also be used as a scrubbing media for residual chlorine dioxide produced and used up in mill bleach plants.
It is used to remove hair from hides before processing for leather and in preparation of sodium polysulfide immersion which helps to accelerate the dry skin soft.
It is used as a flotation agent in copper mining where it is used to activate oxide mineral species. It sulphidizes oxide ores and separates copper from molybdenum by depressing copper from Cu-Mo concentrate allowing for conventional floatation separation.
It is used in waste water treatment to remove heavy toxic metals by precipitation. It is used in the textile industry for the reduction of denitrification and nitrification man-made fiber, cotton fabric dyeing and mordant. It is used in the production of antipyretics phenacetin.