Question

What is the name of ${{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}$ ?

Answer 1

There are two types of inorganic compounds: the iconic and the covalent compounds and there are different rules that are followed in the nomenclature of different inorganic compounds. The compound name shall contain the cation followed by the anion name with the number of atoms of each as prefixes.

Complete answer:
Compounds in which two non-metals are bonded to each other by covalent bonds are called the “molecular compounds''. Among the non-metallic atoms present in these compounds, one with positive oxidation state is written first and the atom of the negative oxidation state is written second. When any two or more nonmetals combine to form two or more compounds than prefixes are used before the name to distinguish them. For example, phosphorus reacts with oxygen to form various compounds.
In case of the compound given above, there are two atoms of phosphorus and five atoms of oxygen and hence the name of the compound is: “diphosphorus pentoxide.” But it is commonly called as: phosphorus pentoxide.

Note:
The ionic compounds are made from the cations of the metals and the anions of the non-metals. Their names end with “-ide”, for example: sodium chloride, calcium chloride, potassium bromide, etc. so the cation is named first and its name is unchanged and the anion is modified to “-ide”.
The transition metal cations, such as iron, copper, nickel, etc. have more than one valances and they are said to have variable valances. As such the higher valent metallic ion is named by the suffix ”ous” while the lower valent ion is named by the suffix “ic”, for example: ferric chloride for the trivalent iron atom and ferrous chloride from the divalent iron atom.