CHEMISTRY GLOSSARY
T-shaped molecular geometry → T-oblik geometrije molekule
T-shape is a molecular geometry that results when there are 3 bonds and 2 lone pairs around the central atom in the molecule. The atoms bonded to the central atom lie at the ends of a T with 90° angles between them. Molecules with an trigonal bipyramidal electron pair geometries have sp3d (or dsp3) hybridization at the central atom. ICl3 has a T-shaped molecular geometry.
tear gas → suzavac
Tear gases is the common name for substances which, in low concentrations, cause pain in the eyes, flow of tears and difficulty in keeping the eyes open. Tear gases are used mainly in military exercises and in riot control, etc., but have also been used as a method of warfare. Irritating gases have been used in war since ancient times but it was not until after the Second World War that a more systematic search for effective substances was started. Among a long series of substances, three have become of greater importance than the others. These substances are chloroacetophenone (codename CN), orto-chlorobenzylidene-malononitrile (CS) and dibenz(b,f)-1,4-oxazepine (CR).
tetrahedral molecular geometry → tetraedarska geometrija molekule
Tetrahedral is a molecular shape that results when there are four bonds and no lone pairs around the central atom in the molecule. The atoms bonded to the central atom lie at the corners of a tetrahedron with 109.5° angles between them. Molecules with an tetrahedral electron pair geometries have sp3 hybridization at the central atom. The ammonium ion (NH4+) and methane (CH4) have a tetrahedral molecular geometry.
thermometer → termometar
Thermometers are devices for measuring temperature. Linear and volume thermal expansion are macroscopic properties of matter, which can be easily measured, relative to measurements of microscopic properties, on the basis of which, temperature is defined. Thermometers based on thermal expansion are secondary instruments that is, they have to be calibrated in comparison to a standard thermometer. In a thermometer with liquid, mercury or alcohol is placed in a small glass container. If temperature increases, the liquid undergoes volume expansion and rises in a capillary. The level of the raised liquid is the measure of temperature. Mercury thermometers measure temperatures in the temperature range between -39 °C and 300 °C. Alcohol thermometers measure lower temperatures. Bimetal thermometers have a spiral spring, which consists of two metals with different coefficients of linear expansion. When temperature changes, metals undergo different change in length and the consequence twisting of the spring is transferred to a pointer, the deflection of which is the measure of temperature.
titanium → titanij
Titanium was discovered by William Gregor (England) in 1791. Named after the Titans, the sons of the Earth goddess in Greek mythology. It is shiny, dark-grey metal. Powdered form burns in air. Exposed surfaces form oxide coating. It can be highly polished and is relatively immune to tarnishing. Unreactive with alkali and most acids. Titanium usually occurs in the minerals ilmenite (FeTiO3), rutile (TiO2) and iron ores. Pure metal produced by heating TiO2 with C and Cl2 to produce TiCl4 then heated with Mg gas in Ar atmosphere. Since it is strong and resists acids it is used in many alloys. Titanium dioxide (TiO2), a white pigment that covers surfaces very well, is used in paint, rubber, paper and many others.
trigonal bipyramidal molecular geometry → trigonska bipiramidalna geometrija molekule
Trigonal bipyramidal (trigonal bipyramidal shape) is a molecular geometry that results when there are five bonds and no lone pairs on the central atom in the molecule. Three of the bonds are arranged along the atom’s equator, with 120° angles between them; the other two are placed at the atom’s axis. Axial bonds are at right angles to the equatorial bonds. Molecules with an trigonal bipyramidal electron pair geometries have sp3d (or dsp3) hybridization at the central atom. The PCl5 molecule has a trigonal bipyramidal molecular geometry.
trigonal planar molecular geometry → trigonska planarna geometrija molekule
Trigonal planar is a molecular shape that results when there are three bonds and no lone pairs around the central atom in the molecule. The pairs are arranged along the central atom’s equator, with 120° angles between them. Molecules with an trigonal planar electron pair geometries have sp2d hybridization at the central atom. The carbonate ion (CO32-) has a trigonal planar geometry.
trigonal pyramidal molecular geometry → trigonska piramidalna geometrija molekule
Trigonal pyramidal is a molecular shape that results when there are three bonds and one lone pair on the central atom in the molecule. Molecules with an tetrahedral electron pair geometries have sp3 hybridization at the central atom. Ammonia (NH3) is a trigonal pyramidal molecule.
triple bond → trostruka veza
Triple bond. (≡) is a covalent bond that involves 3 bonding pairs. In the valence bond theory, one of the bonds in a triple bond is a sigma bond and the other two are pi bonds. For example, the central bond in acetylene is a triple bond: H-C≡C-H.
zinc → cink
Zinc was discovered by Andreas Marggraf (Germany) in 1746. The origin of the name comes from the German word zink. It is bluish-silver, ductile metal. Reacts with alkalis and acids. Tarnishes in air. Zinc is found in the minerals zinc blende (sphalerite) (ZnS), calamine, franklinite, smithsonite (ZnCO3), willemite and zincite (ZnO). Used to coat other metal (galvanizing) to protect them from rusting. Although some 90 % of the zinc is used for galvanizing steel. Zinc metal is used in the common dry-cell battery. Also used in alloys such as brass, bronze. Zinc compounds are also used in the manufacture of paints, cosmetics, plastics, electronic devices, and other products.
Citing this page:
Generalic, Eni. "Spin pair." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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