User Rating: 0 / 5

Star InactiveStar InactiveStar InactiveStar InactiveStar Inactive

A favourable interaction of two electrons with opposite m , values in the same orbital.

Latest Articles

  • Features of the Scanning Tunneling Microscope

    The scanning tunneling microscope (STM) invented by Heinrich Rohrer and Gerd Binnig in the 1980s still manages to do a great job today and competes with more advanced microscope types. The scanning tunneling microscope is used for studying the surface atoms that are found on various materials. The...

  • Protein Design: Automated protein discovery and synthesis

    In this paper I describe (theoretically) the method(s) of automated protein discovery and synthesis.

  • Harmful Chemicals Found In Food

    It's getting close to New Years and many people are starting to think about how to lose those extra pounds they managed to gain over the holidays. There are many sorts of diets and fads that have developed over the years from cutting carbs to cutting protein. Everyone has their own opinion as to...

  • What are Compound Microscopes?

    Most of the microscopes used today are compound. A compound microscope features two or more lenses. A hollow cylinder called the tube connects the two lenses. The top lens, the one people look through, is called the eyepiece. The bottom lens is known as the objective lens. Below the two lenses is...

  • What's In Your Beverage? How to Ensure Quality Control with CO2 Analytical Support

    Calibration standards, performance audits, and the FDA's never-ending safety, labeling, and inspection requirements are just the tip of the iceberg when it comes to dealing with the increasingly stringent quality control standards of the beverage industry. As these quality standards become...

Most Popular


Discovered : by Henry Cavendish in 1766.
Isolated in London, UK.
Origin : The name is derived from the Greek ‘hydro genes’, meaning water forming.
Description :A colourless, odourless gas that burns and can form an explosive mixture with air. It is currently manufactured from methane gas, but is also produced by the electrolysis of water and aqueous salts. The gas is used to make such key materials as ammonia, cyclohexane and methanol, which are intermediates in the production of fertilisers, plastics and pharmaceuticals. Some see hydrogen gas as the clean fuel of the future - generated from water and returning to water when it is oxidised. Hydrogen-powered fuel cells are increasingly being seen as pollution-free sources of energy.

Mole Fraction

The number of moles of a component of a mixture divided by the total number of moles in the mixture.



A compound formed by interaction of sucrose with a metallic oxide, usually lime, and useful in the purification of sugar.


Ionization Isomers

Isomers that result from the interchange of ions inside and outside the coordination sphere.

Weak Electrolyte

A substance that conducts electricity poorly in a dilute aqueous solution.

Hard Water

Water containing Fe3+, Ca2+, and Mg2+ ions, which forms precipates with soap.


Classification of liquid substances that will burn on the basis of flash points. A combustible liquid means any liquid having a flash point at or above 37.8°C (100°F) but below 93.3°C (200°F), except any mixture having components with flash points of 93.3°C (200°F) or higher, the total of which makes up 99 percent or more of the total volume of the mixture.

Osmotic Pressure

The hydrostatic pressure produced on the surface of a semipermable membrane by osmosis.

Hydrolysis Constant

An equilibrium constant for a hydrolysis reaction.

Lewis Base

Any species that can make available a share in an electron pair.

Activity Series

A listing of metals (and hydrogen) in order of decreasing activity.

Specific Heat

The amount of heat required to raise the temperature of one gram of substance one degree Celsius.

Differential Thermal Analysis (DTA)

A technique for observing the temperature, direction, and magnitude of thermally induced transitions in a material by heating/cooling a sample and comparing its temperature with that of an inert reference material under similar conditions.

Dermal toxicity

Adverse health effects resulting from skin exposure ot a substance.


Elements with properties intermediate between metals and nonmetals: B, Al, Si, Ge, As, Sb, Te, Po, and At.

Ternary Acid

A ternary compound containing H, O, and another element, often a nonmetal.


Isomers that differ only in the way that atoms are oriented in space, consist of geometrical and optical isomers.


Bonding Orbital

A molecular orbit lower in energy than any of the atomic orbitals from which it is derived, lends stability to a molecule or ion when populated with electron.

Fossil Fuels

Substances consisting largely of hydrocarbons, derived from decay of organic materials under geological conditions of high pressure and temperature (metamorphism) include coal, petroleum, natural gas, peat and oil shale.  For further information see Fuel Chemistry

Alkyl Group

A group of atoms derived from an alkane by the removal of one hydrogen atom.