Copper sulfate

Crystal structure
__ Cu 2+      __ S      __ O
General
Surname	Copper (II) sulfate
other names	Copper (II) sulphate (VI) Blue vitriol blue Galitzenstein Bluestone COPPER SULFATES ( INCI )
Ratio formula	CuSO 4
Brief description	white to gray, odorless powder (anhydrous) light blue to slightly turquoise crystals (hydrates)
External identifiers / databases
CAS number 7758-98-7 (anhydrous) 7758-99-8 (pentahydrate) 10257-54-2 (monohydrate) EC number 231-847-6 ECHA InfoCard 100,028,952 PubChem 24462 ChemSpider 22870 DrugBank DB06778 Wikidata Q107184
Drug information
ATC code	V03 AB20
properties
Molar mass	159.61 g mol −1 (anhydrous) 249.69 g mol −1 (pentahydrate)
Physical state	firmly
density	3.60 g cm −3 (anhydrous, 20 ° C) 2.286 g cm −3 (pentahydrate, 25 ° C)
Melting point	Decomposes at 560 ° C
solubility	light in water: 203 g l −1 at 20 ° C (anhydrous) 317 g l −1 at 20 ° C (pentahydrate)
safety instructions
Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary Caution H and P phrases H: 302-315-319-410 P: 273-302 + 352-305 + 351 + 338
MAK	0.1 mg m −3 (measured as an inhalable aerosol part)
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Copper sulfate , formerly also copper vitriol (see vitriols ), copper smoke and Galitzenstein , is the copper salt of sulfuric acid and belongs to the group of sulfates . It consists of Cu ²⁺ and SO ₄ ²⁻ ions and is a colorless, non-flammable solid that is very soluble in water. Copper sulfates ( hydrates ) containing water of crystallization , for example copper (II) sulfate pentahydrate, are blue in color.

Occurrence

Copper sulphate occurs naturally as a weathering product of sulphidic copper ores as crust-shaped, granular or fibrous aggregates. The anhydrous form (CuSO ₄ ) does not occur in nature, only the hydrates in the form of the rare minerals chalcanthite (copper sulfate pentahydrate, Cu [SO ₄ ] · 5H ₂ O) and boothite (copper sulfate heptahydrate, Cu [SO ₄ ] · 7H ₂ O). Due to the very good water solubility of copper sulphate, they are only preserved in very dry climatic areas and are therefore only found in deserts such as the Chilean Atacama Desert .

Extraction and presentation

Synthetically produced CuSO ₄  · 5 H ₂ O crystals

In the laboratory, for example, copper sulfate can be produced from copper hydroxide and sulfuric acid:

${\displaystyle \mathrm {\ Cu(OH)_{2}+H_{2}SO_{4}\longrightarrow } }$ ${\displaystyle \mathrm {\ CuSO_{4}+2\ H_{2}O} }$

Technically, copper sulfate is obtained through the action of sulfuric acid on copper (II) oxide or copper (II) sulfide .

${\displaystyle \mathrm {\ CuO+H_{2}SO_{4}\longrightarrow } }$ ${\displaystyle \mathrm {\ CuSO_{4}+H_{2}O} }$

${\displaystyle \mathrm {\ CuS+H_{2}SO_{4}\longrightarrow } }$ ${\displaystyle \mathrm {\ CuSO_{4}+H_{2}S} }$

Copper sulfate is by far the most important copper salt.

properties

Copper sulfate is good in water , not soluble in most organic solvents . It dissolves in glycerine with an emerald green color. With strong heating (from 340 ° C) the anhydrous copper sulfate breaks down into copper (II) oxide and sulfur trioxide .

Hydrates

In addition to the anhydrous compound, there are copper (II) sulfate hydrates containing water of crystallization. The most common is the pentahydrate (CuSO ₄  · 5 H ₂ O). There is also a trihydrate (CuSO ₄  · 3 H ₂ O) and copper (II) sulfate monohydrate (CuSO ₄  · H ₂ O).

Loss of crystal water with CuSO ₄  5 H ₂ O ( TGA / DTA )

Copper sulfate pentahydrate CuSO ₄  · 5 H ₂ O (copper (II) tetraoxosulfate (VI) pentahydrate, mineral name: chalcanthite ) forms triclinic crystals with a blue color, which gradually give off water of crystallization when heated and finally to colorless copper sulfate anhydrate become. At 95 ° C, two water molecules split off, creating the trihydrate. Another two water molecules are split off at 116 ° C, the last one at 200 ° C, the crystals lose their blue color and become colorless copper sulfate CuSO ₄ . This process is reversible: when the anhydrous anhydrate is dissolved in water, the solution turns blue due to the hydration of the Cu ²⁺ ions and warms up ( hydration energy ). The blue copper sulfate pentahydrate can crystallize again from the solution through evaporation of the water. The chemical formula of the pentahydrate should better be written according to [Cu (H ₂ O) ₄ ] SO ₄  · H ₂ O, since four water molecules are coordinated directly to the copper (II) ions in the crystal structure and surround them in a square-planar manner.

use

Copper sulphate is used for a multitude of processes and reactions, for example for copper plating, for the production of copper-containing colors, for copperplate etching, in New Year's rockets (creates a bluish-green hue) and other applications.

In electroplating technology , copper sulphate is used for galvanic copper plating and in the form of Oettel's solution in coulometry to determine exact amounts of charge. It can also be found as an additive in marking paints, which is painted on a metallic surface before marking it, in order to make the actual crack more visible after marking .

When mixed with a calcium hydroxide suspension, copper sulphate was previously used as Bordeaux broth in viticulture to combat fungal diseases. Today pesticides are used that contain copper sulfate or other copper compounds. Modern pesticides containing copper are better formulated and have lower concentrations of copper sulfate, copper oxychloride , copper hydroxide or copper octanoate . Because of possible soil pollution with copper salts, alternatives are being sought (e.g. phosphonates ). The Integrated Viticulture and Organic viticulture have limited the number of output rates of copper-containing agents. However, copper-containing agents in organic viticulture have a central role in the downy mildew .

Dry copper sulfate (white) and in the middle after adding water: copper sulfate pentahydrate (light blue)

The anhydrous, white copper sulfate can be used as a drying agent , for example for the production of anhydrous ethanol . The blue coloration caused by the storage of crystal water can be used to detect water.

In combination with ammonium sulfate , copper sulfate is used against algae in swimming pools. However, it is increasingly being displaced by so-called quaternary ammonium compounds , especially by agents containing benzalkonium chloride , as these are less harmful to water. The copper sulphate does not discolour the water, but overdosing it can cause hair to turn green, especially if combined preparations are used that have to be topped up regularly and contain copper sulphate. Most of the ingredients in these preparations are biodegraded over time, evaporate or are retained in the filter; But copper sulfate remains in the water.

In German Pharmacopoeia anhydrous copper (II) sulphate is a monograph in the European Pharmacopoeia copper (II) sulfate pentahydrate. Copper sulfate used to be used externally as a caustic agent, as astringency and in wound treatment, internally as an emetic, to stop bleeding and as an antidote to phosphorus poisoning. In modern human medicine, copper sulfate is rarely used in various skin diseases, for example because of its astringent properties. In sheep farming and veterinary medicine, copper sulphate is used to treat the dead leg , a bacterial disease of the claws in sheep.

Copper sulfate is very often used for growing crystals , especially in schools .

Biological importance

Oral ingestion of copper sulfate is toxic to humans and can lead to blue-green burns of the mucous membranes, severe vomiting , bloody diarrhea , shock , hemolysis and hemoglobinuria . A lethal course of the intoxication is possible. On the other hand, it is highly toxic to microorganisms and has harmful effects in the aquatic environment. The water-polluting salt is classified in water hazard class 3, highly hazardous.

safety instructions

Contact with strong reducing agents (e.g. finely powdered magnesium ) or hydroxylamine can lead to dangerous reactions with strong heat generation.

literature

• K. Bauer and employees: Viticulture. 8th edition, Austria. Agrarverlag, Vienna 2008, ISBN 978-3-7040-2284-4 .

Web links

Commons : Copper (II) sulfate  - Collection of images, videos and audio files

• Mineral Atlas - Chalcanthite

Individual evidence

1. ↑ Entry on COPPER SULFATE in the CosIng database of the EU Commission, accessed on February 16, 2020.
2. ↑ ^{a b c d e f g h i} entry to copper (II) sulfate in the GESTIS database of IFA , accessed on January 9, 2019(JavaScript required) .
3. ↑ Horst Bannwarth, Bruno P. Kremer: From structure of matter to metabolism: Explore - experience - experiment . BoD - Books on Demand, 2016, ISBN 978-3-8340-0848-0 ( limited preview in Google book search).
4. ↑ Entry on Copper sulphate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
5. ↑ Copper sulfate in PharmaWiki.ch, accessed on: February 2, 2020
6. ↑ Mutschler at el .: Mutschler drug effects , Deutscher Apotheker Verlag, 8th ed.