Sulphate also spelled as Sulfate is a chemical compound that is composed of sulphur and oxygen atoms. It is one of the most widely available chemical compounds accessible as naturally occurring minerals on earth. It is mostly found in the environment as a result of atmospheric and terrestrial processes. The major contributors of sulphate are sulphide containing rocks and minerals, sulphur released from the erosion of evaporite deposits, and even volcanoes. Sulphate is a derivative of salts with a variety of elements including potassium, sodium, calcium, magnesium, and barium.
Sulphate Formula: SO₄²⁻.
Sulphate Structure :[SO4-2]
Let us understand the chemical bonding and molecular structure of sulphate. The sulphate ion is composed of sulphur and oxygen atoms. Here, sulphur is the central atom and it is surrounded by four oxygen atoms that are located at equal distances in the plane. As for the bonding, 2 of the oxygen atoms form S=O bonds, and the other two form S-O- bonds. The oxygen atoms are responsible for the negative charge (-2) of the anion because they are in -2 state.
If we look at the structure or the shape of the molecule, it has a tetrahedral geometry which is further based on the VSEPR theory. Sulphate ion has a star-shaped geometry. It is represented as:
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The atoms are placed at 109.5° angle. To determine the structure students can learn to draw the Lewis structure of sulphate and also know about the formal charges and the total number of valence electrons needed for sulphate.
Properties of Sulphate
The physical and chemical properties of sulphate ions are as given below.
Physical Properties of Sulphate:
Ionic sulphates are easily soluble in water. There are some exceptions such as strontium sulphate, calcium sulphate, barium sulphate, and lead sulphate. These sulphates have less solubility.
Also, they form white precipitates during reactions.
Chemical Properties of Sulphates:
A chemical property of sulphate is that it can easily combine with metals. To expand it further, the oxygen atoms in sulphate ion act as ligands (arms) and they attract the metal to form a bridge or connection. This interlink of a chemical compound bonding with metal is called a chelate.
The sulphate ion acts as a ligand connected either by two oxygens or single oxygen as a bridge. Sulphate has so many electrons, it can use any pair of electrons to connect with a metal.
For example, let us take a neutral metal PSO₄ wherein the sulphate ion acts as a bidentate ligand. The metal and oxygen bonds consist of a particular covalent character in sulfate complexes.
The sulfate ion is a conjugate base of bisulfate ion, HSO₄⁻ (hydrogen sulphate), and a conjugate base of sulphuric acid, H₂SO₄. The organic esters of sulphate like dimethyl sulphate come under esters of sulphuric acid and covalent compounds.
Preparation of Sulphate
There are usually two methods to prepare sulfates.
Oxidation of metal sulphites and sulfides. However, the formation of sulfate as the final state of oxidation may be determined by consecutive reactions that are critically dependent on other factors such as the catalyst, etc.
Sulphates can be prepared by treating metal hydroxide, metal oxide, and pure metal with sulfuric acid. Some of the examples are:
During the preparation of sulfate remember that sulfuric acid should be deprotonated twice, if it occurs only once, then hydrogen sulfate ion is made.
Here are some examples of sulphates.
Iron (II) Sulphate
Sodium Lauryl Sulphate
Sulphates are easily available in nature and also easily synthesized in industries. Therefore, this chemical compound has applications in a wide variety of products. Some of the sulfate uses are listed below.
Magnesium sulfate is used in therapeutic baths.
Sulphate minerals are used in the making of metal salts.
Copper sulfate is the most common algaecide.
They are used in detergents, emulsifiers, and foaming agents.
Gypsum is a natural form of hydrated calcium sulfate used in the making of plasters.
Sulphate compounds are also found in cosmetic products such as toothpaste, body sprays, lotions, make-up, soaps, shampoos, etc.
They are used in construction.
They are powerful surfactants and are found in most products that are used to remove grease from heavy machinery.
Copper sulfate is used in the electricity domain and barium sulfate is used in water treatment.
Sulfites are added to cleaning products to make them more effective cleaners.
Sulphate Effects and Hazards
Some of the popular hazards and health effects are:
Naturally, sulfates can occur as microscopic particles called aerosols which is a result of fossil fuel and biomass combustion. This can lead to an increase in the acidity of the atmosphere and the formation of acid rain.
As for the effects on humans, it can cause dryness of skin, ruin hair cuticles, and they usually leave the hair with a negative charge.
Sulphur and its allotropic forms
Sulphur belongs to group 6 of solid nonmetals in the periodic table along with oxygen and other elements. After oxygen, sulphur is quite a reactive element especially at high temperatures which help in breaking of A-S bonds in S8 molecules. sulphur burns in air and reacts directly with carbon, Phosphorus ,arsenic and many metals . oxidising acids oxidize it into SO₂ and alkalis dissolve it to give sulfides and thiosulfate it reacts with H₂ and halogens. The sulphides are stable compounds and many metals are found in nature in the form of sulphites. In this article we are going to learn various allotropic components of sulphur. The various allotropes of sulphur are rhombic, monoclinic, plastic and amorphous.
Allotropic forms of of sulphur :
sulphur exist in several allotropic forms which may be classified into following categories:
Homocyclic species containing 6-20 sulphur atoms.
a. rhombic orthorhombic sulphur.
b. monoclinic sulphur cyclo S6 form.
different chain polymers known as catena Sn sulphur.
unstable small molecules
preparation of milk sulphur
preparation of colloidal sulphur with hydrogen and nitric acid.
Various forms of sulphur :
sulphur can be classified into various forms like Sulphur dioxide ,sulphur trioxide, sulfuric acid .sulphur has a strong tendency for catenation and chemical reactivity rather than other elements .that is why it can be converted into various other forms .there are various uses of sulphur here are the 10 uses of of sulphur in chemical industry in dyes drugs Paints pigments and detergents in Fertilizer industry in the manufacture of explosives in petroleum refining in Metallurgy in pickling in leather industry for tanning as a laboratory reagent production of Lead Storage batteries as electrolyte