Potassium permanganate is prepared by fusing pyrolusite with caustic potash in the presence of air or some oxidising agent which gives a green mass. The green mass is then extracted with water and treated with a current of `Cl_2` to form potassium permanganate. In the laboratory, it is prepared by oxidising a manganese (II) salt by peroxosulphate. It acts as an oxidising agent in neutral, alkaline or acidic solutions.
What type of hybridisation is involved in `MnO_4^-` ion and what is its structure?

Explanation

To determine the hybridization and structure of the `MnO_4^-` ion (permanganate ion), we can follow these steps:

### Step 1: Determine the Valence Electrons
Manganese (Mn) has an atomic number of 25, and its electron configuration is `[Ar] 3d^5 4s^2`. In the `MnO_4^-` ion, manganese is in the +7 oxidation state. Therefore, it loses 7 electrons (5 from 3d and 2 from 4s), leaving it with no d-electrons in the valence shell.

### Step 2: Count the Total Number of Electrons
The `MnO_4^-` ion consists of one manganese atom and four oxygen atoms. The total number of valence electrons can be calculated as follows:
- Manganese contributes 7 electrons (in +7 oxidation state).
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