Sodium Sulfide - Sodium Leucate

Na ₂ S (78.04). When sodium hydrogen sulfide, obtained by saturating an aqueous solution of sodium hydroxide with hydrogen sulfide, is added to sodium hydroxide and left in a cool place, the nonahydrate is obtained. When the hydrate is heated in a hydrogen stream, it becomes the anhydrous form. The anhydrous form is a colorless cubic crystal. Density 1.86 g cm ^-3 . Melting point 950 °C. It is oxidized in air to produce sodium thiosulfate, and also absorbs water and carbon dioxide to produce sodium carbonate and hydrogen sulfide. The nonahydrate is a colorless tetragonal columnar crystal. Density 1.43 g cm ^{-3 .} It melts at 50 °C and decomposes on ignition. It is deliquescent, and both the anhydrous and hydrate form dissolve well in water, are strongly alkaline, and dissolve in acid to generate hydrogen sulfide (it is also decomposed by water containing carbon dioxide (carbonated water)). It is sparingly soluble in ethanol and insoluble in ether. It dissolves sulfur to produce sodium polysulfides (Na ₂ S _n , n = 2, 3, 4, 5). Sodium tetrasulfide, Na ₂ S ₄ [CAS 12034-39-8], is a yellow cubic crystal. Its melting point is 275 °C. It is soluble in water and ethanol. When the aqueous solution comes into contact with air, it liberates sulfur. It is used as a reducing agent for organic nitro compounds, in the manufacture of sulfur dyes, as a desulfurizing agent, as a depilatory agent for leather tanning, as a digesting agent for pulp, as an analytical reagent, in the manufacture of semiconductors, as a photographic reagent, as an electrolyte for sodium-sulfur batteries, and as a sulfurizing agent for contaminated heavy metals in waste liquids. It is corrosive to the skin. Harmful. [CAS 1313-82-2]

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

Na₂S(78.04)．水酸化ナトリウムの水溶液に硫化水素を飽和させて得られる硫化水素ナトリウムに，水酸化ナトリウムを加え，冷所に放置すると九水和物が得られる．水和物を水素気流中で熱すると無水物となる．無水物は無色の立方晶系．密度1.86 g cm^－3．融点950 ℃．空気中で酸化されてチオ硫酸ナトリウムを生じ，また水分と二酸化炭素を吸収して炭酸ナトリウムと硫化水素を生じる．九水和物は無色の正方晶系柱状晶．密度1.43 g cm^－3．50 ℃ で融解し，強熱すると分解する．潮解性で，無水物，水和物ともに水によく溶け，強アルカリ性を示し，酸に溶けて硫化水素を発生する(二酸化炭素を含む水(炭酸水)によっても分解される)．エタノールに難溶，エーテルに不溶．硫黄を溶解して多硫化ナトリウム(Na₂S_n，n ＝ 2，3，4，5)を生じる．四硫化ナトリウムNa₂S₄[CAS 12034-39-8]は黄色の等軸晶系．融点275 ℃．水，エタノールに可溶．水溶液は空気に触れると硫黄を遊離する．有機ニトロ化合物の還元剤，硫化染料の製造，脱硫剤，皮なめし用の脱毛剤，パルプの蒸解剤，分析試薬，半導体の製造，写真用試薬，ナトリウム-硫黄電池の電解質，廃液などの汚染重金属の硫化剤などに用いられる．皮膚を腐食する．有害．[CAS 1313-82-2]

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