: Zinc Zn=65.38 no30; valence 2; Group IIB element. Abundance in earth's curst:
: 0.02% by wt. Natural isotope(自然界的異構物): 64(48.89%); 66(27.81%);
: 68(18.57%); 67(4.11%); 70(0.62%); eight radioactive isotopes and two isomers.
: Occurs in smithsonite or zinc spar, sphalerite or zinc blende, zincite,
: willemite, franklinite[(Zn,Mn,Fe)O.(Fe,Mn2)O3] or gahnite(ZnAl2O4). Has been
: known since very early times. Commercial forms: ingots; lumps; sheets; wire;
: shot; strips; sticks; granules; mossy; powder(dust).
: 物化性:
: Bluish-white, lustrous metal; distorted hexagonal close-packed structure;
: stable in dry air; becomes covered with a white coating of basic carbonate on
: exposure to moist air. m.p=419.5'C b.p=908'C
: 25
: d =7.14. Heat capacity at constant pressure(25'C): 6.07cal/more'C
: Mohs' hardness(摩氏硬度) =2.5. When heated to 100-150'C becomes malleable
: at 210'C becomes brittle and pulverizable. Burns in air with a bluish-green
: flame.(焰色)
Loses electron in aqueous systems to form Zn2+ E'(aq)Zn/Zn2+=0.763V.
Slowly attacked by H2SO4 or HCl; oxidizing agents or metal ions, e.g. Cu2+,
Ni2+, Co2+, accelerate the process. Reacts slowly with ammonia water and
acetic acid; rapidly with HNO3. Reacts with alkaly hydroxides to form
"zincates", ZnO2 2-, which are actually hydroxo complexes such as Zn(OH)3 -;
Zn(OH)4 2-, [Zn(OH)4(H2O)2] 2-
Human toxicity:
Inhalation(食入) of fumes may result in sweet taste, throat dryness, cough,
weakness, generalized aching, chills, fever, nausea, vomiting. Zinc chloride
fumes have caused injury to mucous membranes and skin irritation. Ingestion
of sol salts may cause nausea, vomiting, purging.
用途:
Galvanizing sheet iron; as ingredient of alloys such as bronze, brass,
Babbitt metal, German silver, and special alloys for die-casting; as a
protective coating for other metals to prevent corrosion; for electrical
apparatus, especially dry cell batteries, household utensils, castings,
printing plates, building materials, railroad car linings, automotive
equipment; as reducing agent in organic chemistry; for dioxidizing bronze;
extracting gold by the cyanide process, purifying fats for soaps; bleaching
bone glue; manuf sodium hydrosulfite; isulin zinc salts; as reagent in
analytical chemistry, e.g., in the Marsh and Gutzeit test for arsenic;
as a reducer in the determination of iron. It's a nutritional trace element.
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