Zinkchlorid

Structural formula
general
name Zinkchlorid
other names Zinkchlorür, Chlorzink
sum formula ZnCl 2
CAS number 7646-85-7
short description white, granular powder
characteristics
mol mass 136,29 g mol
state of aggregation firmly
density 2,91 kg/m ³
melting point 313 °C
boiling point 732 °C
steam pressure - Pa (x °C)
solubility well solubly in water and alcohol
of safety references
of Gefahrensymbole
C
C
corrosive
R and S-sentences

of R: 34
S: 1/2 7/8 28 45

MAK -
As far as possible and common, SI-UNITs are used. If not differently notes, the indicated data apply with standard conditions.

Zinkchlorid (ZnCl 2) is a white, granular powder, which develops when heating up zinc in chlorine or sulfur-sour zinc oxide with calcium chloride, also when the release zinc, zinc oxide or zinc blende in hydrochloric acid.

Table of contents

history

Zinkchlorid was represented 1648 of Glauber from Galmei and 1741 of Pott from zinc.

production and representation

for the representation of pure Zinkchlorid one loosens zinc in hydrochloric acid, whereby the metal must be present in the surplus last, treats the solution with chlorine, in order iron in iron (III) - chloride (FeCl 3) to transform, falls then the iron hydroxide by digesting with zinc oxide, filtered and evaporates, until a drop on a cold porcelain plate solidifies.

With stronger evaporation hydrochloric acid escapes, and the preparation gives then due to the formation of basic zinc a gloomy solution. If one evaporates to dry ones, then one receives a corrosive sublimate with stronger heating up from water-free Zinkchlorid.

Generally speaking one receives Zinkchlorid to yardstick by loosening of zinkischer Ofenbrüche (zinc oxide) in hydrochloric acid, by treating zinc blende with hydrochloric acid, whereby the escaping hydrogen sulfide gas (H 2 S) is used for the sulfuric acid production, furthermore by leaching out roasted blendehaltigen sulfur gravel.

characteristics

water-free Zinkchlorid is whitish, translucent (zinc butter), from the specific weight 2.75, melts with over 100°, distilled with red glow, is very hygroscopically, also very easily soluble in alcohol. The solution with evaporation syrup-like and supplies, with something hydrochloric acid shifted, colorless, very zerfliessliche crystals with 1 molecule water.

Zinkchlorid tastes, works most corrosive , loosens vegetable fiber, extracts from many organic materials in the way like concentrated sulfuric acid the elements of the water, charred for example wood burning, transforms alcohol into ether, paper into greaseproof paper etc.

use

one uses Zinkchlorid for impregnating wood, for the preservation of animal materials, when refining the oil, during the representation of greaseproof paper, ether, stearic acid; with chlorinated lime for bleaching the paper, in the Färberei as if pickle for aniline blue, for the representation of some tar colors and the Garancins, for pickling and coloring the brass, for gluing the paper pulp, for disinfecting, with chemical work as water-extracting means, in the medicine as etching agent, a concentrated solution for even heating up of containers on a certain higher temperature.

A solution of syrup-like Zinkchlorid, with zinc oxide touched, solidifies and gives for out basic Zinkchlorid existing white, very hard mass, which can be used as tooth and Metallkitt, particularly if one something glass powders adds. Also painting, in which zinc oxide chloride forms, was recommended.

Zinkchlorid

one mixes for example 4l acidless chlorine zinc solution of 58° B. with 10l of a solution, which 2 per cent contains char-sour soda, and zinc oxide up to the due consistency sets in addition. This odorless and cheap mixture must be used immediately. The painting is durable, stands however no coloring additives. A solution of Zinkchlorid of the specific weight 1.7, with surplus zinc oxide cooked, loosens silk.

From mixed, very concentrated solutions of Zinkchlorid and ammonia or from a solution of zinc oxide or zinc hydroxide in ammonia ammonium zinc chloride (NH 4) crystallizes 2 [ZnCl 4]. A solution hydrochloric acid concentrated by zinc in, which just as much ammonia contains such as zinc (Lötwasser), serves for soldering, for tin and Verbleien of copper, iron etc.

One can use alternatively in addition, for instance a 30%ige solution of Zinkchlorid in water under additive of little ammonium chloride, acidified with something hydrochloric acid, as Lötwasser. It is used in the technology as wetting and surface activating agent for tinning with approximately 300 degrees Celsius. The Zinkchlorid is able, particularly in the heat on the surfaces e.g. to dissolve from steel finding oxides (Fe 2 O 3) by Komplexbildung to exhaust from the steel surface and to make after tinning a direct contact possible between steel and tin: A firm connection between steel and tin develops.

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