Iodine is a halogen used as a disinfectant active in pharmaceutical antiseptics. It also serves as a catalyst in organic synthesis and as a nutrient additive in animal feed. The material takes the form of dark grey-violet crystals. Recorded packaging formats include 25 kg fibre drums, 1000 kg big bags and bulk. Food use is subject to the applicable food-additive specification and permitted-use conditions. Use in biocidal products depends on the applicable product authorisation. Pharmaceutical use requires the applicable pharmacopoeia grade.