N3

N3 may refer to:

Roads

Transport

Science

Azide

Azide is the anion with the formula N₃⁻. It is the conjugate base of hydrazoic acid (HN₃). N₃⁻ is a linear anion that is isoelectronic with CO₂ and N₂O. Per valence bond theory, azide can be described by several resonance structures, an important one being N⁻=N⁺=N⁻. Azide is also a functional group in organic chemistry, RN₃. The dominant application of azides is as a propellant in air bags.

Preparation

Inorganic azides

Sodium azide is made industrially by the reaction of nitrous oxide, N₂O with sodium amide in liquid ammonia as solvent:

Many inorganic azides can be prepared directly or indirectly from sodium azide. For example, lead azide, used in detonators, may be prepared from the metathesis reaction between lead nitrate and sodium azide. An alternative route is direct reaction of the metal with silver azide dissolved in liquid ammonia. Some azides are produced by treating the carbonate salts with hydrazoic acid.

Organic azides

The principal source of the azide moiety is sodium azide. As a pseudohalogen compound, sodium azide generally displaces an appropriate leaving group (e.g. Br, I, OTs) to give the azido compound. Aryl azides may be prepared by displacement of the appropriate diazonium salt with sodium azide, or trimethylsilyl azide; nucleophilic aromatic substitution is also possible, even with chlorides. Anilines and aromatic hydrazines undergo diazotization, as do alkyl amines and hydrazines.

N3 road (South Africa)

The N3 is a national route in South Africa that connects Johannesburg and Durban, respectively South Africa's largest and third-largest cities. Johannesburg is the financial and commercial heartland of South Africa, while Durban is South Africa's key port and one of the busiest ports in the Southern Hemisphere and is also a holiday destination. Durban is the port through which Johannesburg imports and exports most of its goods. As a result, the N3 is a very busy highway and has a high volume of traffic.

Route

The N3 is divided into 12 sections, starting with section 1 in Durban and ending with section 12 in Johannesburg. Between the two cities, the route passes the following towns and cities: Pietermaritzburg, Estcourt, Ladysmith, Harrismith, Heidelberg and Germiston. It no longer passes through any of these towns, as bypasses have been built around all of them. The last bypass that was built was around the town of Warden.

KwaZulu-Natal

The N3 begins in the Durban Central Business District at Pine Street and Commercial Road as a dual-carriageway freeway and heads west, passing through Berea and Mayville before intersecting with the N2 at the EB Cloete Interchange. It then heads through Westville before bypassing the south of Pinetown. The route is then tolled at Mariannhill as it leaves the urban area, and then heads towards Cato Ridge. From Cato Ridge, the route passes Camperdown before turning towards the northwest and heading towards Pietermaritzburg, the provincial capital.