Cupric chloride, also known as copper (II) chloride, is an inorganic compound with the chemical formula CuCl2. It is a yellow-green crystalline solid that is soluble in water and many organic solvents.

Chemical and Physical Properties
Cupric chloride crystallizes in the orthorhombic crystal system, with each copper ion being surrounded by four chloride ions in a tetrahedral arrangement. It has a melting point of 397°C and a boiling point of 867°C. CuCl2 is hygroscopic in nature, meaning it readily absorbs moisture from air. When dissolved in water, it dissociates into hydrated Cu2+ and Cl- ions. The deep blue color of cupric chloride solutions arises due to the presence of Cu2+ ions. It is soluble in ethanol and acetone as well.

An important physical property of Cupric Chloride is its ability to adopt different oxidation states - it can act as a mild oxidizing agent by accepting electrons. For example, when cupric chloride reacts with metallic zinc, it gets reduced to cuprous chloride (CuCl) while oxidizing Zn to Zn2+. This redox reaction plays a key role in some important applications of cupric chloride.

Production
On an industrial scale, Cupric Chloride is produced by treating copper metal with chlorine gas. The chemical reaction can be represented as:

This reaction is carried out either by bubbling chlorine through a heated mixture of copper and copper (I) chloride or by passing chlorine over heated copper turnings. The product obtained is a yellow-green crystalline solid.

Uses of Cupric Chloride
Some major uses of cupric chloride include:

- Electroplating: It is used as an electrolyte for electroplatingapplications like electroplating copper onto steel, producing brass, bronze, etc. Its ability to dissolve copper makes it suitable.

- Production of other chemicals: Cupric chloride finds use in manufacturing other chemicals like cuprous chloride, copper metal, cupric oxide, copper resinate, etc. which have applications in industries like dye, paint, wood preservative etc.

- Catalyst: Finely divided cupric chloride is used as a catalyst for oxidation of methanol to formaldehyde, oxidation of cyclohexane to adipic acid.

- Wood preservative: Creosote containing cupric chloride is used to treat wood and prevent decay caused by fungi or insects. The copper ions have biocidal properties.

- Photography: In old photographic processes, solutions of cupric chloride were used as a toner to increase contrast.

Safety and Handling
Being a strong oxidizing agent as well as an irritant, cupric chloride demands careful handling and safety precautions. Skin contact should be avoided as it can cause irritation, burns and even allergic reactions in sensitive individuals. Inhalation of dust or fumes formed during heating should also be limited. It is non-flammable but may ignite combustible materials. Spillages should be cleaned up immediately using absorbent materials like vermiculite and disposed properly. As with any chemical, proper protective equipment like gloves, eye wear etc. must be used.

Environmental Impacts and Regulations
The environmental impacts of cupric chloride arise mainly from the release of heavy metal copper and chlorine ions into waterways. Copper is toxic to aquatic organisms even at low levels. Chloride contamination can affect soil and water quality. Most countries have regulations regarding the maximum allowable limits of heavy metals in industrial effluents. Proper wastewater treatment is necessary before discharging into sewers. The sludge from treatment also needs careful handling and disposal as per local hazardous waste management norms. Overall, as a persistent pollutant, manufacturing units of cupric chloride require strict adherence to environmental standards.

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