can anyone help me on this? The final result i want to achieve is as attached.

To summarize:

1. Select the cell that you want to split into two parts.
2. Click on the "Data" tab in the ribbon at the top of the Excel window.
3. Click on the "Text to Columns" button in the "Data Tools" group.
4. In the "Convert Text to Columns Wizard" that appears, select "Delimited" and click "Next".
5. In the next screen, select the delimiter that separates the two parts of the cell. In your example, it looks like a comma (",") is used. Make sure the preview pane shows the correct separation of the two parts.
6. Click "Next" and then choose the data format for each column. In your example, the first column should be formatted as "General" and the second column should be formatted as "Text".
7. Click "Finish" and the cell will be split into two parts.

If you need to split more cells in the same way, you can select the range of cells and follow the same steps.

Cells cannot be split in excel, but they can be merged, which would still achieve what you're looking for.
Select the two cells that you want to merge, then click on "Merge & Center" in the Alignment group (Home toolbar), or click on the Alignment group arrow and select Merge Cells.

The top left cell is not actually split, it just has a diagonal line through it. Right click on the cell, select Format Cell, Borders, click on the box to insert a diagonal line (click again to remove if you put it in the wrong place).

Type X(g/L) with a bunch of spaces in front of it, then Alt Enter, then G(gL). Make sure the cell is aligned to the left.
This should get the first bit to appear above the diagonal line, and the second bit to appear below it.