1. The problem statement, all variables and given/known data Mercury (II) sulfide. HgS, occurs in two forms. One is red pigment known as vermillion; the other is black. In both, the color is due to band gap transitions (BGT). Which form has the larger band gap? 2. Relevant equations In weak field octahedral complexes, DELTA is relatively small. Are the d-d transitions in these complexes more likely to make the complex red or blue? 3. The attempt at a solution for my first question I believe the answer is Red. for my second question I believe the answer is blue.