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Sodium polysulfide is a general term for salts with the formula Na 2 S x, where x = 2 to 5. The species S x 2−, called polysulfide anions, include disulfide (S 2 2−), trisulfide (S 3 2−), tetrasulfide (S 4 2−), and pentasulfide (S 5 2−). In principle, but not in practice, the chain lengths could be longer.
The compound (C 5 H 5) 2 TiS 5 is an example of a polysulfide complex. Polysulfides are a class of chemical compounds derived from anionic chains of sulfur atoms. [1] There are two main classes of polysulfides: inorganic and organic. The inorganic polysulfides have the general formula S 2− n. These anions are the conjugate bases of ...
Sodium sulfide is a chemical compound with the formula Na 2 S, or more commonly its hydrate Na 2 S·9H 2 O.Both the anhydrous and the hydrated salts in pure crystalline form are colorless solids, although technical grades of sodium sulfide are generally yellow to brick red owing to the presence of polysulfides and commonly supplied as a crystalline mass, in flake form, or as a fused solid.
The rank x of the polysulfide is an important variable. [vague] Crosslinking agents are used, such as 1,2,3-trichloropropane. An idealized polymer is represented by this formula HS(CH 2 CH 2 OCH 2 OCH 2 CH 2 SS) n CH 2 CH 2 OCH 2 OCH 2 CH 2 SH. Thiol-terminated resins can be cured oxidatively. [2]
Potassium pentasulfide is the inorganic compound with the formula K 2 S 5. It is a red-orange solid that dissolves in water. It is a red-orange solid that dissolves in water. The salt decomposes rapidly in air.
Hydrogen disulfide can be synthesised by cracking polysulfanes (H 2 S n) according to this idealized equation: H 2 S n → H 2 S 2 + S n−2. The main impurity is trisulfane (H 2 S 3). [1] The precursor polysulfane is produced by the reaction of hydrochloric acid with aqueous sodium polysulfide. The polysulfane precipitates as an oil. [1] [2]
Intermediate compounds of these also exist, for example thioperoxides (also known as oxasulfides) such as hydrogen thioperoxide, have the formula R 1 OSR 2 (equivalently R 2 SOR 1). These are isomeric to sulfoxides in a similar manner to the above; i.e. >S=O rather than −S−O−.
Sometimes as a mixture with other polysulfides, sodium tetrasulfide is used to produce the polymer called thiokol. The reaction involves alkylation with ethylene chloride: Na 2 S 4 + C 2 H 4 Cl 2 → 1/n (C 2 H 4)S x] n + 2 NaCl. These materials, which have the approximate formula (C 2 H 4)S x] n (x ~ 4), are highly resistant to degradation by ...