Compounds are substances that is composed of many identical molecules, which consist of atoms of more than one element held together by chemical bonds. The chemical formula specifies the number of atoms of each element in a compound molecule. For example, in nitrogen monoxide, there are two elements, nitrogen and oxygen with one atom each. Such compounds with two distinct elements are called binary compounds. In this article, we look at the definition, types, and examples of binary compounds.
Binary compound definition
Binary compounds or binary molecules, are made up of two distinct elements. An element is a substance that cannot be further divided into any simpler substance using chemical methods. For example, in aluminum oxide (Al2O3), there are two distinct elements aluminum (Al) and oxygen (O). The number of atoms of the element is not considered for binary compound classification.
Types of binary compounds
- Binary acids
- Binary ionic compounds
- Binary covalent compounds
Binary Acids
Binary acids consist of a hydrogen cation bonded to an anion. They are also called hydracids. The hydrogen proton bonds with the electronegative atoms of group 7 in the periodic table to form binary acids.
Examples of binary acids:
- Hydrochloric acid – HCI
- Hydrobromic acid – HBr
- Hydroiodic acid -HI
- Hydrofluoric acid -HF
Binary ionic compounds
They are mainly salts which consist of only 2 elements. The first atom or cation in a binary ionic compound is a metal, while the second atom or anion is a non-metal. Binary ionic compounds tend to have relatively high melting and boiling points due to the ionic bond. They dissolve in water to yield electrolytes. They can be generally synthesized by a neutralization reaction between an acid and a base. The name of a binary ionic compound can be written as: Metal + non-metal “ -ide”. The oxidation of the metal can also be used in name if known like aluminum (III) oxide, manganese (II) oxide, etc.
Examples of binary ionic compounds:
- NaCI – Sodium chloride
- NaF – sodium fluoride
- MgO – Magnesium oxide
- AI2O3 – Aluminum oxide
Binary covalent compounds
Binary covalent compounds are composed of two elements bonded together by covalent bonds. They are formed when two non-metals form a covalent bond. Often two non–metals combine in a variety of ratios. Prefixes are used in the names of binary compounds to indicate the number of atoms of each non-metal present.
How to name binary covalent compounds?
RULE 1: The element with a lower group number is written first in the name. The element with a higher group number is written second in the name.
RULE 2: If both the elements are in the same group, the elements with a higher period number are written first in the name.
RULE 3: The second element in the name is named as if it were an anion.
RULE 4: If the compound contains one atom of the element that is written first in the name, the prefix “mono” is not used. Like in nitrogen dioxide, we do not write mono nitrogen oxide.
You can go to this link for a quick quiz on the nomenclature.
Examples of binary covalent compounds:
- Dinitrogen monoxide – N2O
- Nitrogen monoxide – NO
- Nitrogen dioxide-NO2
- Dinitrogen trioxide- N2O3
See also
Neutralization reaction
Examples of neutralization reaction
Concentration of ore
Conductivity of water
Benedict’s test
15 differences between oxidation reaction and reduction reaction
