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
Copper(II) chlorate also. It has also been used to colour copper brown. Copper(II) chlorate Copper(II) chlorate is a chemical compound of the transition metal copper and the chlorate anion with basic formula Cu(ClO). Copper chlorate is an oxidiser. It commonly crystallizes with four molecules of water. Copper chlorate can be made by combining a hot one molar solution of copper sulfate, with barium chlorate, which results in the precipitation of barium sulfate. When the solution is filtered, cooled and evaporated under a vacuum blue crystals form. In 1902 A Meusser investigated solubility of copper chlorate. He found that it melted and started