Themes for home preparation
The structure of atoms and oxidation states of titanium subgroup elements. Peculiarities of hafnium position in the periodic system. Obtaining of titanium, zirconium and hafnium, their properties, reactions with acids. Oxides, hydroxides and salts of titanium (IV), zirconium (IV), hafnium (IV). Salts of oxytitane and oxyzirconium. Titanates and zirconates. Compounds of titanium (III).
Carbides and nitrides of titanium and zirconium. Application of titanium, zirconium, hafnium and their compounds Questions and tasks
1. How do titanium subgroup elements react with acids and alkalis?
2. What simple substances titanium subgroup elements react with? Give the equations of the relevant reactions.
3. What the content of iodide method of titanium purification? What other metals can be purified in this way?
4. How do acid-base properties in the range TiO2 - ZrO2 - HfO2 change?
5. How are - and - titanium hydroxides received? Compare chemical properties of these compounds.
6. Explain, do ions Ti4+ exist in water solution? Why?
7. Why are titanium compounds with oxidation state less than four more stable, than those of zirconium and hafnium?
Make the equations o f the reaction
TiO2 + C + Cl2 =
Ti + HCl =
Zr + HF =
Ti + C =
Zr + O2 =
TiO2 + H2SO4 =
TiO(OH)2 + HCl =
TiOCl2 + Zn + HCl =
TiCl4 + Mg =
Ti + HF =
Zr + HF + HNO3 =
Ti + N2 =
TiO2
+ NaOH
TiOSO4 + NaOH =
TiCl4 + H2O =
TiCl3 + O2 + H2O =
Experimental section
2. Chemical properties of titanium
2.1. Put 1 microspatula of titanium dust into a test tube and add 4-6 drops of concentrated hydrochloric acid. What can you observe? 2-3 minutes later heat up the test tube cautiously. Write down your observations and the equation of the reaction. What oxidation state does titanium have in compound formed?
2.2. Put 1 microspatula of titanium dust into a test tube and add 4-6 drops of diluted acetic acid. What can you observe? 2-3 minutes later add few crystals of ammonium fluoride. Write down your observations and the relevant equations of the reactions.
2.3. Place 2-3 drops of 0,5N titanyl sulphate solution into each of two test tubes and add 1-3 drops of diluted sodium hydroxide solution in each one until precipitate forms. To this precipitate add 3-5 drops of 2M solution: of hydrochloric acid into the first, of sodium hydroxide into the other. What can you observe? Give the equations of the relevant reactions and make a conclusion on acid-base properties of the obtained precipitate.
2.4. Place 2-3 drops of 0,5N titanyl sulphate solution into a test tube and add 2-3 drops of litmus neutral solution. What can you observe? Give the equations of the hydrolysis in the molecular and ionic forms.
2.5. Place 4-6 drops of 0,5N solution of titanyl chloride into a test tube, add 4-6 drops of concentrated hydrochloric acid and 2-3 granules of zinc. What can you observe? Give the equations of the relevant reactions and explain the discolouration of the solution.
Gadolinite is a mineral of a nearly black color and vitreous luster, and consisting principally of the silicates of cerium, lanthanum, neodymium, yttrium, beryllium, and iron with formula: (Ce,La,Nd,Y)2FeBe2Si2O10. Called gadolinite-(Ce) or gadolinite-(Y) depending on the prominence of the variable element composition (namely, Y if it has more yttrium, and Ce if it has more cerium).
Gadolinite is fairly rare, but it forms attractive crystals that some collectors desire. Its hardness is between 6.5 and 7, and its specific gravity is between 4.0 and 4.7. It fractures in a conchoidal pattern. The mineral's streak is grayish-green. It is also Pyrognomic, which means that it becomes incandescent at a relatively low temperature.
Gadolinite was named in 1800 for Johan Gadolin, the Finnish mineralogist-chemist who first isolated an oxide of the rare earth element yttrium from the mineral in 1792. The rare earth gadolinium was also named for him. However, gadolinite does not contain more than trace amounts of gadolinium. When Gadolin analyzed this mineral, he missed an opportunity to discover a second element: what he thought was aluminium (alumina) was in fact an element that would not be officially discovered until 1798: beryllium (beryllia).