nature : TeO2 white crystalline powder. No foul. Crystal relative density 1.40 5.66 (0 ° C). Ramps side Crystal relative density of 5.91 (0 ° C). 733 ° C melting point. Extremely difficult to dissolve in water, do not dissolve in ammonia, acid and alkali - soluble. And for the preservation of vaccines using bacteria. Tellurium in the air by burning or oxidation of nitric acid from heat.