Barium green color. Barium sulfate is used as an insoluble additive to oil well drilling fluid, as well as in a purer form, as X-ray radiocontrast agents for imaging the human gastrointestinal tract. The soluble barium ion and soluble compounds are poisonous, and have been used as rodenticides. Barium is a soft, silvery-white metal, with a slight golden shade when ultrapure. The silvery-white color of barium metal rapidly vanishes upon oxidation in air yielding a dark gray oxide layer. Barium has a medium specific weight and good electrical conductivity. Ultrapure barium is very difficult to prepare, and therefore many properties of
Barium nitrate nitrate decomposes to barium oxide: Barium nitrate is used in the production of BaO-containing materials. Although no longer produced, Baratol is an explosive composed of barium nitrate, TNT and binder; the high density of barium nitrate results in baratol being quite dense as well. Barium nitrate mixed with aluminium powder, a formula for flash powder, is highly explosive. It is mixed with thermite to form Thermate-TH3, used in military thermite grenades. Barium nitrate was also a primary ingredient in the "SR 365" incendiary charge used by the British in the "De Wilde" incendiary ammunition with which they armed their interceptor