What are Some Prominent Features of Mercury?

Mercury is a chemical element and it is 80th in the periodic table. Commonly known as mercury. There are also other names such as "white magpie, maidservant, magpie, magic glue, yuanshui, lead essence, flowing beads, yuan beads, red mercury, sand mercury, spiritual fluid, living treasure, Ziming" and so on. The element symbol Hg, which is located in the sixth period of the chemical element periodic table, group IIB, is the only metal that exists in liquid state at normal temperature and pressure (in the strict sense, gallium (symbol Ga, element 31)) and cesium ( Symbol Cs, element 55) is also liquid at room temperature (29.76 ° C and 28.44 ° C). Mercury is a silvery white shiny heavy liquid with stable chemical properties. It is insoluble in acids and alkalis. Mercury evaporates at room temperature, and most of the mercury vapor and mercury compounds are highly toxic (chronic). Mercury has a long history of use and a wide range of uses. ^[1] In the medieval alchemy, it was called the sacred three elements of alchemy with sulfur and salt.

It is the only metal that exists in liquid state at normal temperature and pressure. Melting point -38.87 ° C, boiling point 356.6 ° C, density 13.59 g / cm3.

It dissolves in nitric acid and hot concentrated sulfuric acid, and generates mercury nitrate and mercury sulfate, respectively. Mercury salts appear in excess of mercury. Can dissolve many metals and form alloys, alloys are called

It should be noted that traces of liquid mercury will generally not cause serious toxic reactions ^[11]

Mercury from "

The most common applications of mercury are in the manufacture of industrial chemicals and their use in electronic or electrical products. Mercury is also used in thermometers, especially those that measure high temperatures. More and more gaseous mercury is still used in the manufacture of fluorescent lamps, and many other applications have been gradually phased out due to health and safety issues, and replaced by the less toxic but much more expensive Galinstan alloy. In addition, the uses of mercury are:

Since gold can be broken down from its minerals, it is often used in gold ores.

Instruments such as barometers and diffusion pumps.

The triple point is -38.8344 ° C, which is a standard point for temperature.

Gaseous mercury is used in mercury vapor lamps.

Used to make liquid mirror telescopes. The telescope that uses the rotation to make the liquid form a parabolic shape, and uses it as a main mirror for astronomical observation, is one-third the price of an ordinary telescope.

Other uses: Mercury switches, pesticides, in the production of chlorine and potassium hydroxide, preservatives, used as electrodes, batteries and catalysts in some electrolytic equipment.

In nature, mercury mostly exists as a compound. Mercury is copper and sulfur, so most of the mercury

Mercury detection methods

Determination of total mercury

Atomic fluorescence spectrometry:

Principle: After the sample is digested by acid heating, in an acidic medium, the mercury in the sample is reduced to atomic mercury by potassium borohydride (KBH ₄ ) or sodium borohydride (NaBH ₄ ). In the atomizer, under the irradiation of a special mercury hollow cathode lamp, the ground state mercury atoms are excited to a high-energy state, and when deactivated back to the ground state, they emit fluorescence with a characteristic wavelength, and the fluorescence intensity is directly proportional to the mercury content and is in line with the standard More quantitative.

Cold atomic absorption spectrometry:

Principle: Mercury vapor has a strong absorption effect on the resonance line with a wavelength of 253.7nm. The sample undergoes acid digestion or catalytic acid digestion to change the mercury to an ionic state. In a strongly acidic medium, stannous chloride is reduced to elemental mercury. Using nitrogen or dry air as a carrier, elemental mercury is blown into a mercury analyzer and cooled. Atomic absorption measurement, in a certain concentration range, its absorption value is directly proportional to the mercury content, and is more quantitative than the standard series.

Dithizone colorimetry:

Principle: After the sample is digested, the mercury ion can form an orange-red complex with dithizone in an acidic solution, which is soluble in chloroform and compared with the standard series for quantitative analysis.

Methylmercury determination

Gas chromatography:

Principle: The methylmercury in the sample is ground with sodium chloride and added with copper ion-containing hydrochloric acid (1 + 11). After complete extraction, the supernatant is adjusted to a certain acidity by centrifugation or filtration, and mercapto cotton is used. Adsorption, elution with hydrochloric acid (1 + 5), and finally methylmercury was extracted with benzene and analyzed by gas chromatography with an electron capture identifier.

Cold atomic absorption method:

Principle: Same as gas chromatography. However, it is determined in a basic medium with a mercury detector and compared with the standard series. ^[15]

Handling of mercury leaks

The widely used thermometers, sphygmomanometers, and other equipment have caused environmental problems such as mercury easily contaminating the room. Break the mercury temperature timer indoors. Don't be alarmed. You can immediately use the paper to see the broken mercury beads. It cannot be stained with mercury, which is extremely unscientific and irresponsible.) Put it in a sealed water bottle. If there are tiny mercury beads, you can push them together with a piece of paper, and the mercury will automatically gather into small balls and then collect them. . For safety, in the case of some simple chemicals, you can use nitric acid to wipe the mercury-contaminated ground to completely eliminate mercury pollution. The method of covering with sulfur powder must not be used, because mercury is difficult to combine with sulfur at normal temperature, and mercury pollution cannot be removed. In order to completely remove mercury pollution, you can use the iodine vapor fumigation method to fumigate the chamber several times until the cuprous iodide test paper does not change color. ^[12] Experiments have shown that the daily leakage of mercury can be adhered and collected with scotch tape commonly used in households. The effect is better than that of paper. Mercury leakage from thermometers and sphygmomanometers can be treated with this method.