Black mercury sulfide

Mercuric sulfide. See Mercury sulfide (ic), black Mercury sulfide (ic), red Mercuriphenyl acetate. See Phenylmercuric acetate... 

Mercury (II) sulfide Mercury sulfide, black. See Mercury sulfide (ic), black Mercury sulfide (ic), black CAS 1344-48-5 EINECS/ELINCS 215-696-3 Synonyms Mercuric sulfide Mercury (II) sulfide Mercury sulfide, black Empirical HgS... 

Vermilion and cinnabar are two bright red, toxic minerals that share an identical composition (they are both composed of mercury sulfide) but have different crystal structures. Two kinds of vermilion are known one of natural origin and another made artificially. Finely ground natural vermilion may vary in hue from red to liver-brown and even to black. Artificial vermilion was made from mercury and sulfur the method of preparation seems to have been developed by the Chinese and was introduced into Europe only during the eighth century c.e. (Gettens et al. 1972). 

Mercury is a relatively rare chemical element. In the lithosphere it occurs mainly as sulfides, HgS. Mercury sulfide comes in two forms cinnibar, which is black, and vermillion. In some places mercury exists in a small proportion as free chemical species. 

When mercury is rubbed with powdered sulfur or mixed with molten sulfur, black mercury(ll) sulfide is formed. When heated with an aqueous solution of potassium pentasulfide, mercury(ll) sulfide is obtained as a scarlet product, known as vermillion and used as an artist s pigment. 

The product on exposure to light gradually converts to black mercury(ll) sulfide. 

The black mercury(ll) sulfide is prepared usually by precipitation from an aqueous solution of mercury(ll) salt with hydrogen sulfide. Thus, when H2S is passed into a solution of HgCb, a pale yellow precipitate of composition HgCb 2HgS forms. This converts to amorphous black HgS on further treatment with H2S. 

When hydrogen sulfide reacts, with mercuric chloride in neutral or acid solution, or when mercury and sulfur are ground together, black mercuric sulfide is formed. Under certain conditions, this material can be converted into the red modification by the continued action of soluble alkali sulfides. The reaction of mercuric chloride and sodium thiosulfate gives the red form if the ratio of the concentrations is higher than 1 4d The red sulfide is also produced when the substance Hg(SH)NCS is boiled with concentrated ammonium thiocyanate solution or when hydrogen sulfide is conducted into a warm mercuric salt solution in the presence of acetic acid and an excess of ammonium thiocyanate, or thiourea.2,3... 

Four different thiourea complexes of mercury(II) are easily prepared from aqueous solutions of mercury(II) chloride and thiourea. The proportions of reagents are not as critical as the temperature, elevation of which results in precipitation of black mercury (II) sulfide. Electrical conductivities and freezing points provide evidence for the constitution of the complexes. 

Mix the mercury with an equal amount of native sulfur in a mortar, grinding it together well. The matter will turn black during this process, forming mercury sulfide. Examine the... 

Color Silver-white (liquid metal) tin-white White (solid mercury) Black or grayish-black (mercuric sulfide, black) bright scarlet-red blackens on exposure to light (mercuric sulfide, red) White... 

Weiss SH, Wands JR, Yardley JH. 1973. Demonstration by electron defraction of black mercuric sulfide (b-HgS) in a case of "melanosis coli and black kidneys" caused by chronic inorganic mercury poisoning. Lab Invest 401-402. 

Obviously these equilibria can be disturbed with simultaneous precipitation of black mercury(II) sulfide, not only by the action of hydrogen ions but also by the addition of ions or compounds which remove sulfide ions. The occurrence of reactions that remove sulfide ions can be revealed in this way even in those cases in which the reactions with alkah sulfide are not directly visible, for example with alkali cyanates and arsenites. No change is observed with sodium sulfide, whereas mercury(II) sulfide precipitates if sulfomercu-rate is used. 

Since antimony sulfide is commonly grey to black in colour, parallels are drawn with the black and red forms of mercury sulfide (see mercury sulfides group). However, there is no clear... 

The mercury sulfide compounds are undoubtedly the most important of the mercury group pigments as they include the red mineral cinnabar (HgS) and its synthetic analogue mercury(ll) sulfide, commonly known as vermilion q.v.). Two other crystal modifications of mercury(ll) sulfide occur, the hypercinnabar tyqie (P-HgS) and the metacinnabar type (a -HgS), the latter primarily significant as a black alteration product. Additionally, cadmium mercury sulfide ((Cd,Hg)S) is relevant in the context of cadmium sulfide pigments. 

Mercury(II) chloride is a weakly dissociated salt. When hydrogen sulfide is slowly passed into its solution, a pale yellow precipitate due to HgCb 2HgS is first formed, which on further treatment with H2S converts to black amorphous HgS ... 

Mercury(II) sulfide occurs in nature as the mineral cinnabar. This is the red sulfide of mercury, which is the principle source of all mercury produced in the world. The black sulfide, known as metacinnabar, occurs rarely in nature, sometimes coexisting with the red form and found as a black deposit over cinnabar. 

The black sulfide may also be made by other methods such as adding sodium thiosulfate, Na2S203 in excess to a dilute solution of sodium mercurichlo-ride, Na2HgCl4 and treating mercury with molten or powdered sulfur. Reactions... 

Black precipitate (in neutral or acid medium) of mercury (I) sulfide and mercury... 

A further design of exploding rifle bullet, without a firing pin, contained a primer with 40 mg mercury fulminate in the nose of the bullet which on impact ignited compressed black powder and this in turn detonated a metal cup containing an explosive mixture of potassium chlorate (56%) and antimony sulfide (44%). PETN explosive has also been used in exploding rifle bullets. 

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