Binary Compounds

Introduction

The compounds such as salt that we see in our everyday life are none other than binary compounds. The lattice structure of salt is called rock salt structure. By this structure, we can see the arrangement of different ions of sodium and chlorine in a lattice. These ions of sodium and chlorine make a binary system of sodium chloride lattice. The study of such structures of binary compounds is key to understanding the properties of different materials. The branch of chemistry involves the synthesis and construction of potential materials to improve their physical properties such as elasticity, strength, conductivity etc.

What are Binary Compounds?

The compounds which are made up of two different elements are called binary compounds. An element is a substance that cannot be broken down into smaller substances. These binary compounds are the simplest category of molecular compounds. Binary compounds are also known as binary phase compounds or binary phases. Many such compounds serve as important building blocks of many significant organic and inorganic compounds. One such important compound is water. Water is made up of two elements that are hydrogen and oxygen. Water is a covalent binary compound which has a V-shape. The water molecule constitutes 2 hydrogen atoms inked with a covalent bond to an oxygen atom that has 2 lone pairs of electrons.

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The Naming of Binary Compounds

The process of naming binary compounds is similar to the naming of any other compounds. The IUPAC nomenclature involves.

• The name of the cation present in the binary compound is written first.

• The name of the anion present in the binary compound is written after the name of the cation.

• The name of the anion constitutes the name of the element with the '-ide' suffix. Such as an anion of fluorine is called fluoride.

• For example - KCl is named potassium chloride. Here the potassium ion is a cation while the chloride ion is an anion.

• If the binary compound contains more than two atoms of two elements then the name of the ion includes the number of ions of the same element

• For example - $\mathrm{N_{2}O_{3}}$ is named dinitrogen trioxide. Since there are 2 nitrogen atoms a suffix 'di' is added before nitrogen and similarly, there are 3 oxygen atoms, therefore, a suffix 'tri is added before oxide.

• In the case of binary compounds that have transition metals as cations, the name of the cation is followed by the oxidation state of the cation in roman numerals.

• For example -  $\mathrm{FeO}$ has been named iron (II) oxide. The oxidation state of iron is +2 therefore a roman numeral denoting two is added after the name of the cation.

Examples of Binary Compounds

Examples of Covalent Binary Compounds

Such compounds contain atoms of two elements joined via covalent bonds.

dinitrogen monoxide, carbon tetrachloride, nitrogen monoxide, hydrogen peroxide, nitrogen dioxide, carbon monoxide, dinitrogen trioxide, methane, dinitrogen tetroxide, ammonia, dinitrogen pentoxide, phosphorous pentachloride, sulphur hexafluoride, etc.

Examples of Ionic Binary Compounds

Such compounds contain ionic bonds that link atoms of two elements.

Potassium fluoride, Sodium chloride, Calcium phosphide, Lithium iodide, Sodium nitride, Potassium bromide, Calcium oxide, Magnesium oxide, Sodium bromide, Zinc oxide, Barium oxide, Aluminium chloride, Calcium hydride, Calcium sulphide, Silver chloride, Barium chloride, Potassium iodide, Magnesium hydride, Barium chloride etc.

Examples of Transition Metal Binary Compounds

Gold (I) iodide, Iron (II) chloride, Iron (III) chloride, Copper (I) oxide, Mercury (II) oxide, Tin (II) fluoride, Copper (II) bromide, Copper (I) iodide, Lead (II) fluoride, Lead (IV) nitride, Nickel (II) sulfide, Chromium (III) iodide, Tin (II) fluoride, Mercury (II) sulfide, Lead (IV) Chloride, Nickel (II) phosphide, Gold (III) Bromide, Cobalt (II) iodide, etc.

Binary Acids

Also known as Hydracids, binary acids are substances that have a non-metallic element along with hydrogen. Along with oxyacids, binary acids make the two categories of acids. Oxyacids consist of a hydrogen atom, an oxygen atom and atoms of other elements. The naming of binary acids involves the prefix 'hydro' followed by the name of the element and then the suffix 'ic' is added at last. For example, $\mathrm{HCl}$ is named hydrochloric acid. Most hydracids are made up of hydrogen and halogens. The strength of these acids is governed by many factors such as the bond energy of bong between anion and hydrogen, the solvation energy of anion, the electron affinity of anion, etc. The strength of the acid is inversely proportional to the strength of the bond between hydrogen and non-metal ion.

Difference between Binary Acids and Binary Compounds

Binary Acids	Binary Compounds
Binary acids are compounds constituting two elements that are hydrogen and nonmetallic element.	Binary compounds are compounds that constitute two elements.
Therefore, it could be stated that all binary acids are binary compounds.	All binary compounds are not binary acids.
Binary acids define a sub-category of binary compounds.	Binary compounds, on the other hand, are a much more broad category of compounds as it does not specify the type of element that should be present in a compound to classify it as a binary compound.
Examples: Hydrochloric Acid, Hydrobromic Acid, Hydrofluoric acid, Hydroiodic acid, etc.	Examples: Dinitrogen monoxide, Carbon tetrachloride, Calcium oxide, etc.

Binary Ionic Compound

The compounds that are made up of atoms of two elements that combine by the electrostatic force of attraction and form an ionic bond are called binary ionic compounds. The most common examples are sodium chloride, magnesium chloride, copper sulphide, potassium iodide, calcium oxide, aluminium fluoride, magnesium chloride, barium chloride, aluminium chloride, hydroiodic acid, hydrochloric acid, etc. The compounds such as $\mathrm{H_{2}O}$ fall under the subcategory binary covalent compounds. The difference in bonding between the atom forms the basis of the classification of binary compounds.

Conclusion

To conclude, binary compounds are compounds that form the basics of general chemistry. A sound understanding of these compounds helps in learning bigger molecules and compounds. Since this category of compounds is a broad category, a wide range of applications are there for these compounds. Binary compounds can be uncategorized into binary covalent compounds, binary ionic compounds, binary acids, binary transition metal compounds, etc. These compounds and their properties are studied in various fields of sciences such as biochemistry, medicine, pharmacy, food science, organic chemistry, inorganic chemistry, analytical chemistry, industrial chemistry, materials chemistry, physical chemistry, biotechnology, polymer chemistry, and engineering, etc.

FAQs

Q1. Is aluminium nitrate a binary compound?

Ans. No, Aluminum Nitrate is not a binary compound because the nitrate ion consists of 2 elements that are nitrogen and oxygen. Therefore, three elements including aluminum are present in the compound which contradicts the definition of binary compounds.

Q2. What prefix is used if 7 atoms of the same element are present in a binary compound?

Ans. The prefix ‘hepta’ is used before the name of the ion of the element.

Q3. Write the chemical formula for Triselenium Hexachloride.

Ans. The chemical formula of Triselenium Hexachloride is $\mathrm{Si_{3}Cl_{6}}$

Q4. Write the chemical formula of Dialuminium Trioxide.

Ans. The chemical formula of Dialuminium Trioxide is $\mathrm{Al_{2}O_{3}}$

Q5. Which binary acid is the strongest among halogen hydracids?

Ans. Hydrogen iodide (HI) is the strongest acid among halogen hydracids.