Chemical Properties
Black powder.Soluble in acids; insoluble in water.
General Description
Black or brownish-black powder. Not a true compound but rather an intimate mixture of metallic mercury and mercuric oxide. Insoluble in water and denser than water (density 9.8 g / cm3). Hence sinks in water.
Air & Water Reactions
Insoluble in water.
Reactivity Profile
Mixtures of "Mercurous oxide，black" with barium oxide react vigorously with hydrogen sulfide in air. Explosions may result [Mellor 10:140. 1946-47]. Dissolves in nitric acid. Reacts with hydrochloric acid to give insoluble mercurous chloride (calomel). Contact of the metal oxide caused the explosive decomposition of hydrogen peroxide [Bretherick 5th ed., 1995]. Mixtures with phosphorus or sulfur explode by impact and friction respectively, [Mellor, 1940, Vol. 4, 77].
Health Hazard
Highly toxic, may be fatal if inhaled, swallowed or absorbed through skin. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
Fire Hazard
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Containers may explode when heated. Runoff may pollute waterways.
Safety Profile
A poison. Flammable
by chemical reaction; an oxiduer. Explosive
reaction with hydrogen peroxide, chlorine +
ethylene. Reacts violently with molten
potassium, molten sodmm, S, (HzS + BaO
+ air). Forms explosive mixtures with
nonmetals [e.g., phosphorus (impactsensitive), sulfur (friction-sensitive)].
Incompatible with alkali metals, reducing
materials. Dangerous; when heated to
decomposition it emits highly toxic fumes of
Hg. See also MERCURY COMPOUNDS,
INORGANIC.
