This is the smallest anion that can form multi-dimensional chain structures in a phenomenon called “dimensional caging.” A solution containing this anion can test for explosive peroxides in stocks of diethyl ether exposed to air. Sulfuric acid and a compound with this anion are the products of the Bunsen reaction used to produce hydrogen gas. Thiosulfate (-5[1])reacts with a mixture of manganese and this anion to quantify (15[1])dissolved oxygen (15[1])in the (15[1])(*) Winkler (10[1]-5[1])method. (10[1])Since this (10[1])weakest ligand (10[1])on the spectrochemical series resembles ice when bonded to silver, (10[3]-5[3])it is used (10[1])to induce (-5[1])nucleation (10[2])during cloud (10[1])seeding. (10[6]-5[5])The blue (10[1])charge-transfer complexes (10[1]-5[1])formed by this monatomic anion make it a useful starch indicator. (10[2])For 10 (10[1])points, (10[1])name (-5[1])this anion (10[1]0[1]-5[1])that is (10[1])the common form (10[1])of an element found in the thyroid. ■END■ (10[13]0[5])