Sulfide

Sulfide, also written sulphide, is one of three groups of sulfur-containing chemical compounds. Inorganic sulphides, organic sulphides (also known as thioethers), and phosphine sulphides are the three forms of sulphides. 

1. Sulfide Inorganic are ionic compounds that contain the negatively charged sulphide ion, S2, and are salts of the extremely weak acid hydrogen sulphide. 

2. Organic sulphides are compounds in which two organic groups are covalently bound to a sulphur atom. 

3. Phosphine sulphides are formed when organic phosphines react with sulphur, forming a covalent and ionic bond between the sulphur atom and the phosphorus atom.

In this article, we will analyse whether H2S is organic or inorganic in a detailed manner.

Physical Properties of Sulfide Inorganic

The only sulphides with some appreciable water solubility and that tend to be mainly ionic are the alkali metals and alkaline-earth metals. Copper and zinc sulphides, on the other hand, are among the least soluble compounds known. Polysulfide solutions are formed when water-soluble metal sulphides are heated in an aqueous solution with elemental sulphur. S42 and S32 anions make up the majority of these solutions. Sulfides play a key role in high-density power sources like lithium and sodium sulphide batteries. M2S, M2S2, M2S4, and M2S5 are the sulphides that have been used in these power sources.

Chemical Properties of Sulfide Inorganic

• Semimetals (metalloids) and certain nonmetallic elements combine to form molecular sulphides or polymeric sulphides with sulphide bridges. The structure of silicon disulfide, SiS2, for example, is made up of infinite chains of SiS4 tetrahedrons with shared edges. (A central silicon atom is surrounded by and bound to four sulphur atoms in each SiS4 tetrahedron.) Phosphorus can be found in a variety of molecular sulphides, including P4S3, P4S4 (two different forms), P4S5, P4S7, P4S9, and P4S10. All of these compounds' structures are derived from a P4 tetrahedron in which PP bonds are substituted with PSP units.

• In carbon disulfide (CS2), both of these phosphorus sulphides are stable, and they all react with water to create phosphoric acid (H3PO4) or other phosphorus oxyacids.

P4S10 + 16H2O → 4H3PO4 + 10H2S

• P4S3 is found in the tips of strike-anywhere matches, and it ignites in the air when the match is rubbed against a rough surface, creating friction. The reaction of phosphorus sulphide with active chemicals in the match head produces a flame. P4S10 is a chemical that is used to make industrial lubricant additives.

• Metal sulphides, or compounds containing a metal atom and the sulphide ion, S2, are formed when most metals react directly with sulphur. Sulfides can be made by reducing a sulphate with carbon or precipitating hydrogen sulphide, H2S, or ammonium sulphide, (NH4)2S, from an acidic or simple aqueous solution. Another process, which is particularly useful for water-soluble sulphides, involves bubbling H2S into a simple metal solution to produce metal hydrogen sulphide or MHS. Metal sulphide is generated by adding another equivalent of metal hydroxide.

NaOH + H2S → NaHS + H2O

NaHS + NaOH → Na2S + H2O

H2S Organic or Inorganic

Do You Know Hydrogen Sulfide Organic or Inorganic?

• The chemical compound hydrogen sulphide has the formula H2S is an inorganic compound. It's a colourless chalcogen hydride gas that smells like rotten eggs. It's flammable, toxic, and corrosive.

• The microbial breakdown of organic matter in the absence of oxygen gas, such as in swamps and sewers, produces hydrogen sulphide; this mechanism is known as anaerobic digestion and is carried out by sulfate-reducing microorganisms. H2S can also be used in volcanic gases, natural gas, and certain well water sources. H2S is produced in small quantities by the human body and is used as a signalling molecule.

Structure of H2S is given below:

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Physical Properties of Hydrogen Sulfide Organic or Inorganic

• Since hydrogen sulphide is slightly denser than air, it can be explosive when mixed with it. Sulfur dioxide (SO2) and water are formed when hydrogen sulphide burns in oxygen with a blue flame. In general, hydrogen sulphide acts as a reducing agent, especially when combined with a base to form SH.

• Sulfur dioxide reacts with hydrogen sulphide to form elemental sulphur and water at high temperatures or in the presence of catalysts. The Claus process, an important industrial method for disposing of hydrogen sulphide, uses this reaction.

• Metal sulphides are insoluble, dark-coloured solids formed when hydrogen sulphide reacts with metal ions. Since lead(II) acetate paper readily converts to lead(II) sulphide, which is black, it is used to detect hydrogen sulphide. As metal sulphides are treated with a strong acid, hydrogen sulphide is often liberated.

Metal Derivatives of Sulfides

Transition metal cation aqueous solutions react with sulphide sources (H2S, NaHS, Na2S) to form solid sulphides. Many of these inorganic sulphides are bound to minerals of similar compositions and have poor solubility in water (see below). The bright yellow species CdS, also known as "cadmium yellow," is a well-known example. Ag2S is the black tarnish that forms on sterling silver. Salts are a term used to describe certain animals. In fact, transition metal sulphides have highly covalent bonding, which gives them semiconductor properties, which are linked to their deep colours. Several of them have practical uses as pigments, solar cells, and catalysts.

H2S Organic or Inorganic Biosynthesis

H2S has been shown to be involved in physiological processes such as animal vasodilation, seed germination, and plant stress responses. Hydrogen sulphide signalling is also inextricably linked to physiological processes that are known to be influenced by reactive oxygen and nitrogen species (ROS and RNS) (RNS). H2S has been shown to interact with NO, causing a variety of cellular effects as well as the formation of nitrosothiol, a new signal. Hydrogen Sulfide is also known to raise glutathione levels in cells, which reduces or disrupts ROS levels.

The field of H2S biology has progressed from environmental toxicology to studying the functions of endogenously derived H2S in physiological and pathophysiological states. Pathophysiological states with H2S overproduction (e.g. cancer, Down Syndrome) and pathophysiological states with H2S deficiency (e.g. vascular disease) may be distinguished according to existing classification. While our understanding of H2S biology has progressed dramatically in the last decade, several questions remain, such as how to measure endogenous H2S levels.

Did You Know?

Many metals, including steel, stainless steel, and copper, are highly susceptible to dissolved free sulphides (H2S, HS, and S2). Stress corrosion cracking (SCC) of steel is caused by sulphides in an aqueous solution and is also known as sulphide stress cracking. Corrosion is a major issue in many sulfide-processing facilities, including sulphide ore mills, deep oil wells, pipelines carrying soured oil, and Kraft paper mills.

Sulfate-reducing bacteria produce sulphide, which is released into the air and oxidised in sulfuric acid by sulphur oxidising bacteria, causing microbially-induced corrosion (MIC) or biogenic sulphide corrosion. Biogenic sulfuric acid reacts with sewerage products, causing mass loss, sewer pipe breaking, and, eventually, structural failure. This type of degradation is a common occurrence in sewage systems around the world, resulting in exorbitant repair costs.