halogenider

Halogenider are compounds containing halogens—fluorine, chlorine, bromine, iodine, and sometimes astatine—bonded to another element or group. The term encompasses inorganic halides as well as organohalides (organic halides), and is used in several languages to refer to halide compounds.

Inorganic halides: Halides formed with metals or hydrogen are often ionic salts containing the halide ion X−. Common examples include sodium chloride (NaCl), potassium bromide (KBr), and calcium fluoride (CaF2). These compounds typically exhibit high melting points and significant water solubility. Hydrogen halides such as HF, HCl, HBr, and HI form acids when dissolved in water, with increasing acidity down the group for hydrohalic acids.

Organic halides: Compounds in which a halogen is bonded to carbon are grouped as alkyl halides (R−X) and aryl halides (Ar−X). They are widely used in synthesis and materials science. Reactions include nucleophilic substitution (SN1, SN2), elimination, and various cross-coupling processes. The reactivity depends on the halogen and the substrate: carbon–fluorine bonds are strong and often slow to react, while carbon–iodine bonds are comparatively weaker and more reactive in radical processes.

Properties and considerations: Halogenider span a spectrum from strongly ionic to covalent, depending on bonding context. Halide ions are common nucleophiles and leaving groups in organic reactions. Environmental and health aspects vary; organohalides such as chlorinated solvents and certain pesticides can be toxic and persistent, prompting regulation and remediation efforts.