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Air Liquide

The world leader in gases, technologies and services for Industry and Health, Air Liquide is present in 80 countries with approximately 68,000 employees and serves more than 3 million customers and patients*. Oxygen, nitrogen and hydrogen are essential small molecules for life, matter and energy.​ They embody Air Liquide’s scientific territory and have been at the core of the company’s activities since its creation in 1902. For more information


An industrial process, an equipment or a medical device using a gas or a gas mixture

Auto-ignition temperature

It is the temperature from which a substance spontaneously ignites in air, in the absence of an external energy source. This parameter depends on the pressure and composition of the mixture in air. The autoignition temperature depends on the equivalent ratio and there is a minimum. This minimum value is considered to be the combustible's minimum self-ignition temperature in air, and is referenced in the tables.  



The action of using chemicals to whiten and/or desinfect matter such as chlothing, wood pulp and material surfaces.


Carrier Gas

The gas used to carry vapor through the column of a gas-liquid chromatograph, known as the mobile phase

CAS number

The Chemicals Abstracts Service (CAS) assigns this number to each chemical substance, whether it is a specific molecule, a mixture of isomers, or a product created from a defined industrial process. Considering the complexity of the chemical nomenclature and the possibility to designate a chemical substance by several names, the CAS number makes it possible to identify each compound without any ambiguity.

Critical Point

This point is defined by a temperature and a pressure at which, for a pure substance, the properties of the two phases (liquid and vapor) are identical. On a phase equilibrium diagram, it is the highest temperature and pressure of the Liquid-Vapor saturation curve.


The use of termperatures below -150°C  to condense organic compounds contained in air or in a gas mixture with objective to clean the gas and/or to recycle the organic compounds.



The metallurgy process of reducing the carbon content of a metals, usually steel.



In this process, a chemical is used to removed layers from the surface of a metal surface. A masking material is used to protect the surface not to be removed. Originally used to create artistic printing, it is today a key process for the fabrication of semi-conductors.



A process used to preserve a perishable product or make material more convenient for transport by removing the water in contain.  Also called freeze-drying, it is taking place in two steps : first the material is frozen, and then the surrounding pressure is lowered so as to release the solid water as gas (sublimation).



A chemical reaction between two species that entails the redistribution of chemical bonds. In olefin metathesis, fragment of alkenes are redistributed between two species by the scission and formation of carbon-carbon double bonds.



In oxy-fuel cutting, a torch is used to heat metal to is autoignition temperature. A stream of oxygen in trained on the metal along the cutting line. The metal once burnt, flows out as a metal oxide slag.


Reflow  Soldering

Reflow soldering is a method of assembling metal components on a circuit board surface



When taken above its critical temperature and pressure, a gas is becoming a supercritical fluid, combining liquid and gas properties.



Triple Point

In a pressure-temperature phase diagram, the triple point is defined by the pressure and temperature at which a pure substance (one sort of molecule) can be together liquid, gas and solid. Its three physical states coexist. The three phrase equilibrium curves (Liquid/Vapor, Solid/Liquid and Solid/Vapor) meet at the triple point.


UN Code 

A Substance ID Code for goods whose transport is regulated. It is expressed as a a four digit ID number, as for example : the UN code for argon in a gaseous state is UN1006 and in a refrigerated liquid state is UN1951.



A wafer is a thin (less than 1 mm) circular (typically from 25 to 300 mm) slide of semiconductor material such as crystalline silicon. Wafer are used for the fabrication of integrated circuits, semiconductor devices (transistors, ...) and photovoltaic cells