The compound formed between Ba (Barium) and S (Sulfur) is Barium sulfide, with the chemical formula BaS.

Here's why:

* Barium (Ba) is an alkaline earth metal in group 2, meaning it has a +2 charge.

* Sulfur (S) is a non-metal in group 16, meaning it has a -2 charge.

To form a neutral compound, the charges must balance out. Therefore, one barium atom (Ba²⁺) combines with one sulfur atom (S²⁻) to form BaS.