CHEMISTRY GLOSSARY

radium    →   radij

Radium was discovered by Marie and Pierre Curie (France) in 1898. The origin of the name comes from the Latin word radius meaning ray. It is silvery-white radioactive metal. Reacts with oxygen and water. Highly radiotoxic. Carcinogen by inhalation, ingestion, or exposure. Radium is found in uranium ores at 1 part per 3 million parts uranium. Used in treating cancer because of the gamma rays it gives off.

referent electrode    →   referentna elektroda

Referent electrode is an electrode whose potential is known and completely independent of analyte concentration. Mostly used referent electrodes are calomel and silver/silver chloride electrode.

Table: Dependence of referent electrodes potentials on KCl concentration

rhenium    →   renij

Rhenium was discovered by Walter Noddack, Ida Tacke and Otto Berg (Germany) in 1925. The origin of the name comes from the Latin word Rhenus meaning river Rhine. It is rare and costly, dense, silvery-white metal. Tarnishes in moist air. Resists corrosion and oxidation. Dissolves in nitric and sulfuric acids. Has a very high melting point. Rhenium is found in small amounts in gadolinite and molybdenite. Mixed with tungsten or platinum to make filaments for mass spectrographs. Its main value is as a trace alloying agent for hardening metal components that are subjected to continuous frictional forces.

rhodium    →   rodij

Rhodium was discovered by William Hyde Wollaston (England) in 1804. The origin of the name comes from the Greek word rhodon meaning rose. It is hard, silvery-white metal. Inert in air and acids. Reacts with fused alkalis. Rhodium is obtained as a by-product of nickel production. Used as a coating to prevent wear on high quality science equipment and with platinum to make thermocouples.

rubidium    →   rubidij

Rubidium was discovered by Robert Bunsen and Gustav Kirchhoff (Germany) in 1861. The origin of the name comes from the Latin word rubidius meaning dark red or deepest red. It is soft, silvery-white, highly reactive metal. Ignites in air. Reacts violently with water or oxidants. Rubidium occurs abundantly, but so widespread that production is limited. Usually obtained from lithium production. Used as a catalyst, photocells and vacuum and cathode-ray tubes.

ruthenium    →   rutenij

Ruthenium was discovered by Karl Karlovich Klaus (Russia) in 1844. The origin of the name comes from the Latin word Ruthenia meaning Russia. It is rare, extremely brittle, silver-grey metal. Unaffected by air, water or acids. Reacts with very hot (molten) alkalis. Ruthenium is found in pentlandite and pyroxinite. Used to harden platinum and palladium. Aircraft magnetos use platinum alloy with 10 % ruthenium.

samarium    →   samarij

Samarium was discovered by Paul Emile Lecoq de Boisbaudran (France) in 1879. Named after the mineral samarskite. It is silvery rare earth metal. Stable in dry air. Oxide coating forms on surfaces exposed to moist air. Metal ignites and burns readily. Reacts with water. Samarium is found with other rare earths in monazite sand. It is used in the electronics and ceramics industries. It is easily magnetized and very difficult to demagnetise. This suggests important future applications in solid-state and superconductor technologies.

scandium    →   skandij

Scandium was discovered by Lars Fredrik Nilson (Sweden) in 1879. The origin of the name comes from the Latin word Scandia meaning Scandinavia. It is fairly soft, silvery-white metal. Burns easily. Tarnishes readily in air. Reaction with water releases hydrogen. Reacts with air and halogens. Scandium occurs mainly in the minerals thortveitile (~34 % scandium) and wiikite. Also in some tin and tungsten ores. Pure scandium is obtained as a by-product of uranium refining. Scandium metal is used in some aerospace applications. Scandium oxide (Sc₂O₂) is used in the manufacture of high-intensity electric lamps. Scandium iodide (ScI₃) is used in lamps that produce light having a colour closely matching natural sunlight.

sodium    →   natrij

Sodium was discovered by Sir Humphry Davy (England) in 1807. The origin of the name comes from the Latin word natrium meaning sodium carbonate. It is soft silvery-white metal. Fresh surfaces oxidize rapidly. Reacts vigorously, even violently with water. Reacts with water to give off flammable gas. Burns in air with a brilliant white flame. Sodium is obtained by electrolysis of melted sodium chloride (salt), borax and cryolite. Metallic sodium is vital in the manufacture of organic compounds. Sodium chloride (NaCl) is table salt. Liquid sodium is used to cool nuclear reactors.

sol    →   sol

Sols are dispersions of small solid particles in a liquid. The particles may be macromolecules or may be clusters of small molecules. Lyophobic sols are those in which there is no affinity between the dispersed phase and the liquid (e.g. silver chloride dispersed in water). Lyophobic sols are inherently unstable, in time the particles aggregate, and form a precipitate. Lyiophilic sols, on the other hand, are more like true solutions in which the solute molecules are large and have an affinity for the solvent (e.g. starch in water). Association colloids are systems in which the dispersed phase consists of clusters of molecules that have lyophobic and lyophilic parts (e.g. soap in water).