Examples are mercury, lead, nickel, arsenic, and cadmium. Refinement of sulfidic zinc ores produces large volumes of sulfur dioxide and cadmium vapor. Other arsenic alloys include the II-V semiconductor cadmium arsenide. Alloying elements such as copper, antimony, bismuth, cadmium, and silver increase its hardness. ISO 4520 specifies chromate conversion coatings on electroplated zinc and cadmium coatings. These include such metals as zinc, magnesium, and cadmium. It uses nickel oxide hydroxide and metallic cadmium as electrodes. Dots may also be made from ternary compounds such as cadmium selenide sulfide. Compounds containing cadmium are also carcinogenic. Secondary products include lead, silver, gold, molybdenum, germanium, indium and cadmium. The pigment is a nontoxic alternative to cadmium sulfide pigments. The operation involved spraying large areas with zinc cadmium sulfide. Important monochalcogenides include some pigments, notably cadmium sulfide. Group 12 metals (zinc, cadmium and mercury) are known to make alloys with sodium. The stearate salts of zinc, calcium, cadmium, and lead are used to soften PVC.