Chemical element the elements, including consideration of their general physical and chemical properties, their states of matter under familiar conditions, their melting and boiling points, their densities, their crystal structures as solids, and their origins. Several terms are commonly used to characterize the general physical and chemical properties of the chemical elements. A first distinction is between metals, which readily conduct electricity, nonmetals, which do not, and a small group, (the "metalloids"), having intermediate properties and often behaving as semiconductors. A more refined classification is often shown in colored presentations of the periodic table. This system restricts the terms "metal" and "nonmetal"
Cobalt(III) hydroxide at –30 to –35°С, then adding a 15% solution of sodium carbonate in water with intense stirring. The resulting dark green powder is fairly stable at liquid nitrogen temperature, but at room temperature it turns dark brown within a few days. Cobalt(III) hydroxide Cobalt(III) hydroxide or cobaltic hydroxide is a chemical compound with formula or . It is an ionic compound, with trivalent cobalt cations and hydroxyl anions . The compound is known in two structurally different forms, "brownish-black" and "green". The brownish-black form is a stable solid and can be prepared by reaction of water solutions of cobalt(II) chloride