Iodine in biology 65% of the molecular weight of T4 and 59% of T3. The thyroid gland actively absorbs iodine from the blood to produce and release these hormones into the blood, actions which are regulated by a second hormone, called thyroid-stimulating hormone (TSH), which is produced by the pituitary gland. Thyroid hormones are phylogenetically very old molecules which are synthesized by most multicellular organisms, and which even have some effect on unicellular organisms. Thyroid hormones play a fundamental role in biology, acting upon gene transcription mechanisms to regulate the basal metabolic rate. T3 acts on small intestine cells and adipocytes to increase
Iodine monofluoride −45 °C in CClF: It can also be generated by the reaction of iodine with iodine trifluoride at −78 °C in CClF: The reaction of iodine with silver(I) fluoride at 0 °C also yields iodine monofluoride: Iodine monofluoride is used to produce pure nitrogen triiodide: Iodine monofluoride Iodine monofluoride is an interhalogen compound of iodine and fluorine with formula IF. It is a chocolate-brown solid that decomposes at 0 C, disproportionating to elemental iodine and iodine pentafluoride: However, its molecular properties can still be precisely determined by spectroscopy: the iodine-fluorine distance is 190.9 pm and the I−F bond dissociation energy