Question

MnO exhibits:

• A. Ferrimagnetism
• B. Antiferromagnetism
• C. Ferromagnetism
• D. Paramagnetism

Hint:

MnO shows antiferromagnetism due to opposite alignment of magnetic moments that cancel out.

Answer 1

The Correct Option is B

To determine the magnetic property exhibited by MnO, we need to understand how its atomic structure contributes to its magnetic behavior. The magnetic properties of a material depend on the alignment of its magnetic dipole moments.

1. **Understanding the Concept of Antiferromagnetism**:

• Antiferromagnetism is a type of magnetic ordering in which the magnetic moments of atoms or molecules, usually related to the spin of electrons, align in a regular pattern with neighboring spins pointing in opposite directions.
• This results in a net magnetic moment of zero for the material as a whole because the opposing magnetic moments cancel each other out.

2. **Explanation for MnO**:

• MnO (manganese(II) oxide) is known to exhibit antiferromagnetism. This is due to the arrangement of manganese ions within the crystal lattice structure where adjacent Mn ions have opposite spins.
• In the crystal structure of MnO, each Mn²⁺ ion has unpaired electrons which contribute to the spin. These spins are aligned antiparallel to the neighboring ions' spins, resulting in an overall cancellation of the magnetic moments.

3. **Ruling out Other Options**:

• Ferromagnetism involves all magnetic moments aligning parallel, which is not the case in MnO.
• Ferrimagnetism involves unequal opposing magnetic moments resulting in a net magnetic moment, but this isn't applicable to MnO as its moments cancel out completely.
• Paramagnetism occurs when there are unpaired electrons acting independently, leading to a net magnetic moment only in an external magnetic field. MnO, being antiferromagnetic, doesn't display this independent magnetic behavior.

Therefore, based on the atomic structure and the alignment of magnetic moments, the correct answer is that MnO exhibits Antiferromagnetism.