CHEMISTRY GLOSSARY

fusion    →   fuzija

Fusion is nuclear reaction in which atomic nuclei are brought together into a larger nucleus, releasing a large amount of energy. It is also used in the production of hydrogen bombs.

heterocyclic compounds    →   heterociklički spojevi

Heterocyclic compounds are cyclic compounds having as ring members atoms of at least two different elements, e.g., quinoline, 1,2-thiazole.

cross-linking    →   umrežavanje

Cross-linking is an attachment of two chains of polymer molecules by bridges, composed of either an element, a group, or a compound, that join certain carbon atoms of the chains by primary chemical bonds, as indicated in the schematic diagram

Cross-linking occurs in nature in substances made up of polypeptide chains that are joined by the disulfide bonds of the cysteine residue, as in keratins or insulin. Cross-linking can be artificially effected, either adding a chemical substance (cross-linking agent), or by subjecting the polymer to high-energy radiation. Examples are: vulcanisation of rubber with sulphur, cross-linking of polystyrene with divinylbenzene, or cross-linking of polyethylene by means of high-energy radiation.

Cross-linking has the effect of changing a plastic from thermoplastic to thermosetting. Thus, it also increases strength, heat and electrical resistance, and especially resistance to solvents and other chemicals.

cubic close-packed structure    →   kubična gusta slagalina

In a cubic close-packed (ccp) arrangement of atoms, the unit cell consists of four layers of atoms. The top and bottom layers (a) contain six atoms at the corners of a hexagon and one atom at the center of each hexagon. The atoms in the second layer (b) fit into depressions in the first layer. The atoms in the third layer (c) occupy a different set of depressions than those in the first. The cubic close packed structure can be made by piling layers in the a-b-c-a-b-c-a-b-c... sequence.

cyclic compound    →   ciklički spoj

Cyclic describing a compound that has a ring of atoms in its molecules. In homocyclic compounds all the atoms in the ring are of the same type, e.g. benzene (C₆H₆) and cyclohexane (C₆H₁₂). These two examples are also examples of carbocyclic compounds; i.e. the rings are made of carbon atoms. If different atoms occur in the ring, as in pyridine (C₅H₅N), the compound is said to be heterocyclic.

ion    →   ion

Ion is an atomic or molecular particle having a net electric charge. Positively charged ions are cations, negatively charged ones anions.

ionisation energy    →   energija ionizacije

Ionisation energy is the minimum energy required to remove an electron from an isolated atom or molecule (in its vibrational ground state) in the gaseous phase.

isobars    →   izobari

Isobars are nuclides having the same mass number but different atomic numbers. ⁵⁴Cr and ⁵⁴Fe, ¹¹²Cd and ¹¹²Sn are isobars.

isoelectronic    →   izoelektronske čestice

Isoelectronic refers to a group of atoms or ions having the same number of electrons. For example, F^-, Ne, and Na⁺ are isoelectronics.

decay series    →   raspadni niz

Decay series is a series of decay in which radioactive element is decomposed in different elements until it produces one stable atom.