Iodometry, Photographic processing, Gold extraction, Aluminium cation reaction, Medical uses – antidote to cyanide poisoning,  used as treatment of calciphylaxis in hemodialysis patients with end-stage renal disease, used in the management of extravasations during chemotherapy, in foot baths for prophylaxis of ringworm, in measuring the volume of extracellular body fluid and the renal glomerular filtration rate, As a component in hand warmers and other chemical heating pads,