Treverdige

Treverdige is a term used in Norwegian chemistry to denote valence three. It describes atoms, ions, or molecules that can form three covalent bonds. In English, the equivalent term is trivalent or three-valent. The concept is used to classify elements, functional groups, and coordination in inorganic and organic chemistry, and it helps describe bonding patterns and reactivity.

Etymology and usage notes: The adjective treverdige is formed from tre- meaning three and verdige, historically connected to chemical valence or bonding capacity. In modern Norwegian, treverdig is often used interchangeably with treverdige, and the term appears in both educational texts and some technical writings.

Examples and applications: Ammonia (NH3) is typically described as treverdige nitrogen, since nitrogen forms three N–H bonds. Boron trihalides, such as BF3 and BCl3, are examples of trivalent boron compounds. In organic chemistry, a treverdige functional group is one that can form three bonds; glycerol (propane-1,2,3-triol) is a prototypical treverdige alkohol, having three hydroxyl groups. The notion also applies to molecules with three reactive sites or three substituents around a central atom, i.e., tri-functional or three-coordinate species.

Modern context: While treverdige remains a valid Norwegian term, many technical texts prefer the international term trivalent. The concept aligns with ideas of valence and coordination number three and is used to describe bonding patterns, reactivity, and molecular geometry.

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