Halides are a class of chemical compounds that contain a halogen atom, such as fluorine, chlorine, bromine, or iodine, bonded to a metal. These compounds are also known as salts, as they are formed by the reaction of a metal with a halogen.

Halides can be classified as either ionic or covalent, depending on the nature of the bonding between the metal and the halogen. Ionic halides have a metal cation and a halide anion, while covalent halides have a shared pair of electrons between the metal and halogen atoms.

Halides have a wide range of applications, including as catalysts, pigments, and pharmaceuticals. They are also used in the production of electronics, such as semiconductors and photovoltaic cells. Halides can also be found naturally in minerals and in seawater.

Metal halides

Metal halides are compounds among metals and incandescent lamp. Some, for example, sodium chloride are ionic, while others are covalently reinforced. A couple of metal halides are discrete particles, for example, uranium hexafluoride, however most take on polymeric designs, like palladium chloride.

Sodium chloride crystal structure

Discrete UF₆ molecules

Infinite chains of one form of palladium chloride

Alkali metal halide

In science, soluble base metal halides, or salt halides, are the group of inorganic mixtures with the compound equation MX, where M is an antacid metal and X is a halogen. These mixtures are the frequently economically critical wellsprings of these metals and halides. The most popular of these mixtures is sodium chloride, table salt.

Silver halide

A silver halide (or silver salt) is one of the synthetic mixtures that can shape between the component silver (Ag) and one of the incandescent light. Specifically, bromine (Br), chlorine (Cl), iodine (I) and fluorine (F) may each join with silver to deliver silver bromide (AgBr), silver chloride (AgCl), silver iodide (AgI), and four types of silver fluoride, separately.

Collectively, they are frequently alluded to as the silver halides, and are in many cases given the pseudo-synthetic documentation AgX. Albeit most silver halides include silver molecules with oxidation conditions of +1 (Ag+), silver halides in which the silver particles have oxidation conditions of +2 (Ag2+) are known, of which silver(II) fluoride is the main known stable one.

Silver halides are light-delicate synthetics, and are generally utilized in visual film and paper.

Acyl halide

In natural science, an acyl halide (otherwise called a corrosive halide) is a substance compound got from an oxoacid by supplanting a hydroxyl bunch (−OH) with a halide bunch (−X, where X is a halogen).

On the off chance that the corrosive is a carboxylic corrosive (−C(=O)OH), the compound contains a −C(=O)X utilitarian gathering, which comprises of a carbonyl gathering (C=O) independently clung to a halogen iota. The overall equation for such an acyl halide can be composed RCOX, where R might be, for instance, an alkyl bunch, CO is the carbonyl gathering, and X addresses the halide, like chloride. Acyl chlorides are the most regularly experienced acyl halides, yet acetyl iodide is the one delivered (briefly) on the biggest scale. Billions of kilograms are created yearly in the development of acidic corrosive.

Vinyl halide

In natural science, a vinyl halide is a compound with the equation CH2=CHX (X = halide). The term vinyl is frequently used to depict any alkenyl bunch. Thus, alkenyl halides with the recipe RCH=CHX are at times called vinyl halides. According to the point of view of utilizations, the predominant individual from this class of mixtures is vinyl chloride, which is delivered on the size of millions of tons each year as a forerunner to polyvinyl chloride. Polyvinyl fluoride is another business item. Related compounds incorporate vinylidene chloride and vinylidene fluoride.

Case Study on Halides

One common use of halides is in the production of photovoltaic cells for solar panels. Specifically, thin-film solar cells, also known as second-generation solar cells, often utilize copper indium gallium selenide (CIGS) as the light-absorbing layer. In order to improve the efficiency of CIGS solar cells, researchers have investigated using halide ions, such as chlorine and iodine, to modify the properties of the CIGS layer.

A study published in the journal ACS Applied Materials and Interfaces in 2019 explored the effects of chlorine and iodine doping on the performance of CIGS solar cells. The researchers found that both chlorine and iodine improved the efficiency of the solar cells, with iodine showing the most significant improvement. This is because the halide ions modify the bandgap of the CIGS material, which allows it to absorb more of the solar spectrum and generate more electrical current.

However, the researchers also found that the halide ions can cause unwanted effects, such as reduced stability and increased surface recombination, which can decrease the overall efficiency of the solar cell. They concluded that careful optimization of the halide doping concentration is necessary to balance the positive and negative effects.

This case study demonstrates the importance of halides in the development of renewable energy technologies, but also highlights the need for careful consideration of the potential drawbacks of their use.

White paper on Halides

Introduction:

Halides are a class of chemical compounds that contain a halogen atom, such as fluorine, chlorine, bromine, or iodine, bonded to a metal. These compounds are widely used in various industrial applications, including catalysts, pigments, and pharmaceuticals. Halides are also important in materials science and technology, particularly in the development of semiconductors and photovoltaic cells.

Properties and Structures:

Halides can be classified as either ionic or covalent, depending on the nature of the bonding between the metal and the halogen. Ionic halides have a metal cation and a halide anion, while covalent halides have a shared pair of electrons between the metal and halogen atoms. Halides can also have different crystal structures, such as cubic, tetragonal, or orthorhombic, depending on the size and charge of the metal and halogen atoms.

Applications:

Halides have a wide range of applications in various industries. Some examples include:

• Catalysts: Halides are commonly used as catalysts in organic synthesis reactions, such as Friedel-Crafts reactions and nucleophilic substitutions. Examples of such catalysts include aluminum chloride and palladium chloride.
• Pigments: Halides are used in the production of pigments for paints, inks, and plastics. For example, titanium dioxide can be doped with chlorine or bromine to produce white or yellow pigments.
• Pharmaceuticals: Halides are used in the synthesis of various pharmaceuticals, such as antibiotics and anti-cancer drugs. For example, the anti-cancer drug cisplatin contains a platinum atom bonded to two chlorine atoms and two ammonia molecules.
• Semiconductors: Halides are used in the production of semiconductors, such as gallium arsenide and indium phosphide. The addition of halides can modify the electronic and optical properties of the semiconductor material, allowing for better performance in electronic devices.
• Photovoltaic cells: Halides are used in the production of thin-film solar cells, such as copper indium gallium selenide (CIGS) solar cells. Halide doping can improve the efficiency of the solar cell by modifying the bandgap of the semiconductor material.

Environmental and Health Considerations:

While halides have many important applications, they can also pose environmental and health risks. For example, halides can contribute to acid rain and water pollution if released into the environment. Some halides, such as chlorine and fluorine, can also be toxic if ingested or inhaled in high concentrations. Proper handling, storage, and disposal of halides is important to minimize their environmental and health impact.

Conclusion:

Halides are an important class of compounds that have a wide range of applications in various industries. They can have different structures and properties, depending on the metal and halogen atoms involved. While halides have many important applications, their potential environmental and health risks should be carefully considered and managed. Overall, the development and use of halides is an ongoing area of research and innovation in materials science and technology.