90 | The History and Use of Our Earth’s Chemical Elements high-intensity lamps that produce a natural spectrum, making it useful for stadium lighting.
90 | The History and Use of Our Earth’s Chemical Elements high-intensity lamps that produce a natural spectrum, making it useful for stadium lighting.
It is also used in nickel alkaline storage batteries. Several compounds are used as catalysts to speed up chemical reactions. The radioactive scandium-46 (with a half-life of 83.8 days) emits beta radiation. This property makes it useful as a radioactive tracer in the petroleum industry to monitor fractionation products.
ExamplesofCompounds Not very many compounds of scandium have been found or produced. It has an oxida-
tion state of +3, thus its metallic ion is Sc +++ which means it combines with anions with a –1 oxidation state as follows:
Scandium chloride (ScCl 3 ): Sc 3+ + 3Cl 1- → ScCl 3 . As mentioned, this compound is used in an electrolytic procedure to produce metallic scandium. When scandium ions react with anions with a –2 oxidation state, different compounds result, including, for example, the following two compounds: Scandium oxide (Sc 2 O 3 ): 2Sc 3+ + 3O 2- → Sc 2 O 3 . Scandium oxide is used to prepare scan- dium fluoride (ScF 3 ), which is also used as an electrolyte to produce scandium metal.
3 ]: 2Sc + 3SO 4 → Sc 2 (SO 4 ) 3. This compound is used in the germination of seeds for agricultural plants.
Scandium sulfate [Sc 2 (SO 4 )
Hazards As with other metals, the transition metals and many of their compounds are toxic, and
their powdered or gaseous forms should not be ingested or inhaled. In addition, all but one of the isotopes of scandium are radioactive and should be handled by experienced personnel.
TITANIUM SYMBOL:Ti PERIOD:4 GROUP:4(IVB) ATOMICNO:22
ATOMICMASS:47.88amu VALENCE:2,3,and4 OXIDATIONSTATE:+2,+3,and+4 NATURALSTATE:Solid ORIGINOFNAME:Itwasnamedafter“Titans,”meaningthefirstsonsoftheEarthas statedinGreekmythology. ISOTOPES:Thereare23knownisotopesoftitanium.Allbutfiveareradioactive,ranging fromTi-38toTi-61,andhavehalf-livesvaryingfromafewnanosecondstoafewhours. Thepercentagesofthefivestableisotopesfoundinnatureareasfollows: 46 Ti=8.25%,
47 Ti=7.44%, 48 Ti=73.72%, 49 Ti=5.41%,and 50 Ti=5.18%.
ELECTRONCONFIGURATION EnergyLevels/Shells/Electrons Orbitals/Electrons
s2,p6
3-M=10
s2,p6,d2
4-N=2
s2
Guide to the Elements | 91 Properties
Positioned at the top of group 4 (IVB), titanium heads up a group of metals sometimes referred to as the “titanium group.” Members of this group have some similar properties. Titanium’s density is 4.5 g/cm 3 , which makes it heavier than aluminum but not as heavy as iron. Its melting point is high at 1,660°C, and its boiling point is even higher at 3287°C. Titanium metal is harder than steel but much lighter and does not corrode in seawater, which makes it an excellent alloy metal for use in most environmental conditions. It is also paramagnetic, which means that it is not responsive to magnetic fields. It is not a very good conductor of heat or electricity.
Characteristics As the first element in group 4, titanium has characteristics similar to those of the other
members of this group: Zr, Hf, and Rf. Titanium is a shiny, gray, malleable, and ductile metal capable of being worked into various forms and drawn into wires.
AbundanceandSource Titanium is the ninth most abundant element found in the Earth’s crust, but not in pure
form. It is found in two minerals: rutile, which is titanium dioxide (TiO 2 ), and ilmenite
(FeTiO 3 ). It is also found in some iron ores and in the slag resulting from the production of iron. The mineral rutile is the major source of titanium production in the United States. Although titanium is widely spread over the crust of the Earth, high concentrations of its minerals are scarce. In the past it was separated from it ores by an expensive process of chemical reduction that actually limited the amount of metal produced. A two-step process
involves heating rutile with carbon and chlorine to produce titanium tetrachloride—TiO 2 + C + 2Cl 2 ∆→ TiCl 4 + CO 2 —which is followed by heating the titanium tetrachloride with magnesium in an inert atmosphere: TiCl 4 + 2Mg ∆→ Ti + 2 MgCl 2 . As recently as the year 2000, a method of electrolysis was developed using titanium tetrachloride in a bath of rare-earth salts. This process can be used on a commercial scale that makes the production of titanium much less expensive. Titanium was, and still is, a difficult element to extract from its ore.
Titanium is found throughout the universe and in the stars, the sun, the moon, and the meteorites that land on Earth.
History In 1791 Reverend William Gregor (1761–1817), an amateur mineralogist, discovered
an odd black sandy substance in his neighborhood. Because it was somewhat magnetic, he calculated that it was almost 50% magnetite (a form of iron ore). Most of the remainder of the sample was a reddish-brown powder he dissolved in acid to produce a yellow substance. Thinking he had discovered a new mineral, he named it “menachanite,” after the Menachan region in Cornwall where he lived. During this period, Franz Joseph Muller (1740–1825) also produced a similar substance that he could not identify. In 1793 Martin Heinrich Klaproth (1743–1817), who discovered several new elements and is considered the father of modern analytical chemistry, identified the substance that Gregor called a mineral as a new element.