For any space group the asymmetric unit is a (small) part of the full unit cell. If all symmetry operations of the space group are applied to the asymmetric unit you generate the full content of the unit cell.

As an example take a rectangle. Lets assume that the symmetry of this rectangle contains a mirror plane normal to each of the edges. ( as a consequence you also have a 180 degree rotation through the center of the rectangle) Any of the quarters of such a rectangle would form the asymmetric unit. The two mirror planes and the 180 degree rotation copy this quarter to create all of the rectangle. As a teaching tool you could draw a small molecule inside one of the quarters, and then copy this by the mirror planes. I'd expect that such a 2-D sketch would illustrate the concept of an asymmetric unit.

In your example all atoms of a single molecule form the asymmetric unit. The symmetry operations of space group P3221 will copy this molecule into a group of in total 6 molecules (including the original). "32" in your space group symbol represents a so called three fold screw axis which generates images of the original object that are arranged as a spiral staircase. The second 2 symbolizes a 180 degree rotation which is at 90 degrees to the 32 axis.

Hey there Mahalashmi Srinivasan

Mahalashmi Srinivasan

Mahalashmi Srinivasan

Imagine you Mahalashmi Srinivasan

Now, inside each unit cell, there's a special arrangement of molecules, and that's what we call the "asymmetric unit." It's like the smallest puzzle piece in the crystal structure, and it contains one molecule of the complex.

So, when we talk about "one molecule of the complex in the asymmetric unit," it's like looking at the tiniest part of a big puzzle. And that puzzle is made up of lots of tiny pieces, all stacked up in a special way to form the crystal structure!

I hope that helps you Mahalashmi Srinivasan