Have you ever noticed that everything we see is composed of matter? From the table and chair to humans themselves, everything is matter. Matter can be defined as any substance that occupies space and has mass. We can further classify matter into pure and impure substances.
A substance made up of only one particle is known as a pure substance, while a substance made of more than one particle is known as an impure substance.
We can classify pure substances into compounds and elements. Now the question arises: What is a compound? A compound is a chemical substance made of more than one element chemically bound in a specified ratio. In contrast, an element is the most superficial chemical substance in which all the atoms are identical.
Compound
A compound is a chemical substance made of more than one element that is chemically bound in a specified ratio. Compounds have a remarkable and specified chemical structure held together in a characterised spatial structure by the chemical bonds. For example, the water molecule has a chemical formula H2O implying two hydrogen atoms are bonded to one oxygen atom.
We can further classify compounds into four classes based on the force of attraction between the elements.
- Molecular compounds
- Intermetallic compounds
- Ionic compounds
- Coordination complexes
Molecular compounds
A molecular compound is an electrically neutral group of more than one element retained by chemical bonds. A molecular compound can be homonuclear or heteronuclear based on the composition of elements. Oxygen is an example of a homonuclear molecular compound, while water is an example of a heteronuclear molecular compound.
Intermetallic compounds
An intermetallic compound is a ranked solid-state compound in more than one metallic element. The intermetallic compound is typically rigid and breakable with a high-temperature mechanical property. We can further classify it into stoichiometric or non-stoichiometric intermetallic compounds. Nitinol, niobium-tin, alnico, sendust, permendur, FeCo, and terfenol-D are examples of intermetallic compounds.
Ionic compounds
An ionic compound is an electrically neutral group of ions retained together by an electrostatic force of attraction. An ionic compound consists of a positive charge cation and a negatively charged anion. They have a high boiling and melting point.
Ionic compounds are rigid, brittle and electrically insulator. However, ionic compounds conduct electricity in their molten state or are dissolved in water. Examples of ionic compounds include sodium chloride, magnesium sulphate, and calcium nitrate.
Coordination complexes
A coordination complex comprises a primary central metal atom or metal ion, referred to as a coordination centre. It is further surrounded by an array of molecules and ions known as ligands or complexing agents. The d block metals primarily make it. Penta ammine sulphate cobalt (III) bromide is an example of the coordination complex.
Element
An element is the most superficial chemical substance in which all the atoms are identical. Unlike compounds, they cannot be split into more spartan substances by any chemical reaction. The number of protons in an element’s nucleus is an element’s clarifying property and is equivalent to its atomic number. All atoms with the same atomic number are atoms of the same element.
