CHEMISTRY GLOSSARY

methionine    →   metionin

Methionine is neutral amino acids with polar side chains. It is one of the two sulfur-containing amino acids. Methionine is a fairly hydrophobic amino acid and typically found buried within the interior of a protein. It can form stacking interactions with the aromatic moieties of tryptophan, phenylalanine, and tyrosine. It is an essential amino acid, which means that humans cannot synthesize it, so it must be ingested.

• Abbreviations: Met, M
• IUPAC name: 2-amino-4-methylsulfanylbutanoic acid
• Molecular formula: C₅H₁₁NO₂S
• Molecular weight: 149.21 g/mol

octahedral molecular geometry    →   oktaedarska geometrija molekule

Octahedral molecular geometry (square bipyramidal shape) describes the shape of compounds where six atoms or ligands are symmetrically arranged around a central atom. The sulfur hexafluoride (SF₆), with six bonding pairs, is predicted and found to be a regular octahedron. Four of the attachments are positioned in a square plane with 90° bond angles. The remaining two attachments are positioned perpendicular (90°) to the square plane at opposite ends of the central atom. Molecules with an octahedral electron pair geometries have sp³d² (or d²sp³) hybridization at the central atom.

vulcanisation    →   vulkanizacija

Vulcanisation (vulcanisation of rubber) is a process of combining rubber with sulphur or other substances that causes the polymer chains to crosslink, making them stronger and more elastic.

Zimmermann-Reinhardt’s reagent    →   Zimmermann-Reinhardtov reagens

Zimmermann-Reinhardt’s reagent is a mixture of manganese(II) sulphate, sulphuric acid and phosphorus acid. It is used for preventing oxidation of chloride ion while titrating iron(II) ion with permanganate solution.

oil of vitriol    →   vitriolno ulje

Oil of vitriol is an obsolete name for sulfuric acid (H₂SO₄). Very old way of making sulfuric acid is by heating green vitriol (FeSO₄*7H₂O) to decomposition and collecting the acid vapors evolved.

organic    →   organski

1. Organic refers to any chemical compound based on carbon (C) with the exception of some of the simple compounds of carbon, such as carbon dioxide, which are frequently classified as inorganic compounds. Additional elements that are commonly found in organic compounds are hydrogen (H), nitrogen (N), oxygen (O), phosphorus (P) and sulfur (S).

2. Organic or organically-grown foods are grown or raised without synthetic fertilizers, pesticides, growth stimulators, or antibiotics and other drugs. Pests are controlled by cultivation techniques and the use of pesticides derived from natural sources and the use of natural fertilizers. In addition, organically grown foods must also be stored without the use of chemicals such as artificial additives and preservatives, and without food irradiation.

Petri dish    →   Petrijeva zdjelica

Petri dish is a shallow glass or plastic flat bottomed dish with a lid. Used primarily in laboratories for the culture of bacteria and other microorganisms on specially prepared media. It was named after the German bacteriologist Julius Richard Petri (1852-1921) who invented it in 1877.

pickling    →   dekapiranje

Pickling is a process to chemically remove scale or oxide from steel to obtain a clean surface. When applied to bars or coils prior to bright drawing, the steel is immersed in a bath of dilute sulphuric acid (w(H₂SO₄) = 10 %) heated to a temperature of around 80 °C. An inhibitor is added to prevent attack and pitting of the cleaned metal. After pickling, a washing process takes place followed by immersion in a lime-water bath to neutralise any remaining acid.

selenium    →   selenij

Selenium was discovered by Jöns Jakob Berzelius (Sweden) in 1817. The origin of the name comes from the Greek word selene meaning moon. It is soft metalloid similar to sulfur. Ranges from grey metallic to red glassy appearance. Unaffected by water. Soluble in alkalis and nitric acid. Burns in air. Toxic by inhalation or ingestion. Selenium is obtained from lead, copper and nickel refining. Conducts electricity when struck by light. Light causes it to conduct electricity more easily. It is used in photoelectric cells, TV cameras, xerography machines and as a semiconductor in solar batteries and rectifiers. Also colours glass red.

silver    →   srebro

Silver has been known since ancient times. The origin of the name comes from the Latin word argentum meaning silver. It is silvery-ductile and malleable metal. Stable in water and oxygen. Reacts with sulfur compounds to form black sulfides. Silver is found in ores called argentite (AgS), light ruby silver (Ag₃AsS₃), dark ruby silver (Ag₃SbS₃) and brittle silver. Used in alloys for jewellery and in other compounds for photography. It is also a good conductor, but expensive.