Chemical Bonding and Molecular Structure

The 3-centre-4-electron bond is a model used to explain bonding in hypervalent molecules such as phosphorus pentafluoride, sulfur hexafluoride, the xenon fluorides, and the bifluoride ion.

A sextuple bond is a type of covalent bond involving 12 bonding electrons and in which the bond order is 6. The only known molecules with true sextuple bonds are the diatomic dimolybdenum (Mo2) and ditungsten (W2), which exist in the gaseous phase.

A non-covalent bond is a type of chemical bond, typically between macromolecules, that does not involve the sharing of pairs of electrons, but rather involves more dispersed variations of electromagnetic interactions.

A purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. Purines, including substituted purines and their tautomers, are the most widely distributed kind of nitrogen-containing heterocycle in nature.

Dibenzothiophene is the organosulfur compound consisting of two benzene rings fused to a central thiophene ring. It is a colourless solid .This tricyclic heterocycle, and especially its alkyl substituted derivatives, occur widely in heavier fractions of petroleum.

Heptacene is an organic compound and a polycyclic aromatic hydrocarbon and the seventh member of the acene or polyacene family of linear fused benzene rings. This compound has long been pursued by chemists because of its potential interest in electronic applications.

A glass electrode is a type of ion-selective electrode made of a doped glass membrane that is sensitive to a specific ion. It is an important part of the instrumentation for chemical analysis and physico-chemical studies.

A fluoride selective electrode is a type of ion selective electrode sensitive to the concentration of the fluoride ion. A common example is the lanthanum fluoride electrode.

Lead(II) chloride is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead(II) chloride is one of the most important lead-based reagents. It also occurs naturally in the form of mineral cotunnite.

Mercury(I) chloride is also known as calomel. This dense white or yellowish-white, odourless solid is the principal example of a mercury(I) compound. It is a component of reference electrodes in electrochemistry.

Nickel(II) hydroxide is an insoluble compound commonly used in rechargeable battery electrodes. When charged these electrodes form nickel(III) oxide-hydroxide. Nickel(II) hydroxide is a precipitate formed when the hexaaquanickel(II) ion is mixed with aqueous alkali.

Nitric oxide is an important cell signaling molecule in mammals, including humans. Nitric oxide is an air pollutant produced by combustion of substances in air, like in automobile engines and fossil fuel power plants.

Pentaborane is a colourless mobile liquid with a strong pungent odour (resembling garlic, acetylene or sour milk). In the 1950s it was considered as a good prospect for rocket or jet fuel. Its chemical structure is that of five atoms of boron compounded with nine atoms of hydrogen (B₅H₉).

Phenylphosphine is a primary phosphine. It is the phosphorus analog of aniline. Like all other primary phosphines, phenylphosphine has an intense penetrating odour. It is highly oxidizable, it can function as ligands in complexes, and it is highly nucleophilic.

Hexanes are significant constituents of gasoline. They are all colourless liquids at room temperature with boiling points between 50 and 70 °C and gasoline-like odour. They are widely used as cheap, relatively safe, largely unreactive and easily evaporated non-polar solvents.