Inorganic Sulphides

Sulphides are naturally present as ionic compounds or free anions in mineral-rich rocks like pyrite. These substances are identified as salts that are derived from hydrogen sulfide. A group of metallic elements like zinc, mercury, iron, silver, etc. forms their sulfide compounds that include more than one S2- ion. Their presence is pretty distinguishable owing to the metallic luster of the minerals. To assimilate the definition inorganic sulphide compounds need to be examined based on the below-discussed principles.

Definition inorganic sulphide

The salts arising from very weak acidic samples like hydrogen sulphide (H2S) fall under the definition of inorganic sulphide. These salts are inorganic substances that comprise sulfur anions S2-. These charged particles exhibit a few typical properties which we are going to discuss in this article.

Features typical to inorganic sulphides

• Unlike other sulfide compounds sodium sulphide or Na2S does not contain S2- ions when they are dissolved in water. Na2S is a product occurring from a neutralization reaction between a strong alkali and an acid (weak). Therefore, when dissolved in water, the resultant solution is predominated by OH– anions incorporating a basic nature. The sulfides are replaced by hydrosulphite through the following step:

H2O + (-S2-)       →     SH– + OH–

• The instances where we make sulfide salts to react with acid tend to produce hydrogen sulfide.

-S2- + H+     →     SH–

-SH– + H+     →       H2S

• The chemical reactions that oxidize sulphides involve a complex mechanism. The reaction is largely dependent on the prevalent environment when the process is taking place. Depending on various situations sulphide oxidation may lead to the formation of sulphates (SO42-), sulfites (SO32-), polysulphides, or even sulfur as an independent element.

• Metal sulphides as per the definition inorganic sulphide interact with halogen elements to produce salts of metal and sulfur. Here is an example:

– 8MgS + 8I2 = S8 + 8MgI2

In the beginning, we discussed that sulphides get converted into hydrogen sulphides in addition to salt when they are made to react with an acidic substance. Sulphur is created by oxidizing S2- ions. We find these sulfur traces in reactions that involve metalloids like iodine and chlorine.

MgS + I2 = MgI + S

• Sulphides that are derived from alkaline-earth metals and true metals are not entirely water-soluble. Though most of it dissolves to produce a stable solution. Therefore, we can term these charged particles as ionic entities. Copper sulfide is an exception that does dissolve to produce an aqueous solution.

• It is the hydrogen sulphide that is labeled as toxic but not the sulphites in general. When a selected group of sulfides interact with mineral acids, toxic H2S is formed. It is highly corrosive.

Sulphur is an inorganic compound

In the periodic table, we have noticed the element sulphur which exhibits the atomic number of 16. This element is a yellow-colored non-metal that is discharged along with the emission of natural gas. Sulfur gives off a terrible smell that is comparable to the typical odor of rotten eggs. Humans are well acquainted with sulphur, an inorganic compound in day-to-day life. In nature, this substance showcases inert behavior at room temperature. Sulphur is incorporated within the daily diet to fulfill the micronutrient profile in humans, also doctors prescribe supplementation at times. Shampoos utilize sulfur combined with salicylic acid to get rid of dandruff. The natural abundance is so huge that the entire landmass is estimated to be composed of 3% sulfur. 

Inorganic sulphides examples

Hydrogen sulphide (H2S) is a member of the sulfide family that needs to be handled with care. It is characterized by high flammability, unlike other sulphides. Other sulfides become extremely hot, still, they are not lighted unless they interact with moisture. Sulphides like ammonium hydrosulphide, lead sulphide, potassium sulphide as well as other metallic sulfides are highly basic so they cannot be accessed with acidic principles. Long exposure to sulphides is detrimental to skin health as these are true bases. For example, blindness can occur from very long exposure to concentrated hydrogen sulphide gas. Some other inorganic sulphide examples are selenium disulphide, arsenic sulphide, mercuric sulphide, etc.

Conclusion

Sulphides represent both negatively charged ions of sulphur as well as compounds that contain S2- ions. These compounds are complex matters that are characterized by some unique features which we have discussed as per the chemical datasheet. Inorganic sulphides are found in large amounts and are uniformly distributed throughout the landmass.