1. Iodine is non-metal and has metallic luster;
2. Iodine is solid and easily sublimates, and can be directly changed into gaseous state without passing through liquid state.
3. Pure iodine vapor is dark blue, and the mixed air becomes purple-red.
4. The color of iodine salts is mostly the same as table salt-all are white crystals, with very few exceptions, such as silver iodide is light yellow and copper iodide is golden.
5. Iodine is slightly soluble in water, but more easily soluble in some organic solvents. The color of the iodine solution is purple, red, brown, and dark brown. The darker the color, the more iodine is dissolved.
6, a large amount of iodine is toxic to humans, iodine vapor will irritate the eyes and nasal mucosa severely, and will cause death by poisoning.