220 | The History and Use of Our Earth’s Chemical Elements ExamplesofCompounds
220 | The History and Use of Our Earth’s Chemical Elements ExamplesofCompounds
Common oxidation states for antimony are +3, +5, and –3. A number of compounds are formed with these states. For instance, both chlorine and sulfur antimony compounds are common.
Antimony chloride: Sb 3+ + 3Cl 1- → SbCl 3 . This compound is sometimes called “butter of antimony.” Antimony trisulfide: 2Sb 3+ + 3S 2- . Antimony trisulfide is better known as the mineral stib- nite and is used as a yellow paint pigment and in the manufacture of ruby glass, fireworks, and matches. It is also used to make percussion caps that set off explosives.
Antimony pentoxide (Sb 2 O 3 ) is used as a flame retardant for textile materials and as a source to prepare other antimony compounds.
A unique use of antimony is to make glass that reflects infrared radiation; thus, what is behind the glass cannot be detected by the infrared ray source.
Hazards The powder and dust of antimony are toxic and can cause damage to the lungs. The fumes
of antimony halogens (chlorides and fluorides) are especially dangerous when inhaled or in contact the skin.
Many of the salts of antimony are carcinogenic and can cause lung cancer if inhaled, as well as other cancers if ingested. This is a major hazard with the radioisotopes of antimony used in industry. Some of its sulfide compounds are explosive.
BISMUTH SYMBOL:Bi PERIOD:6 GROUP:15(VA) ATOMICNO:83
ATOMICMASS:208.98038amu VALENCE:3and5 OXIDIATIONSTATE:+3and
+5 NATURALSTATE:Solid ORIGINOFNAME: Bismuthwasknownandusedbytheancientalchemistsalongwith
othermetalsbothforchemicalreactionsandformedicalpurposes.Thenamecomes fromtheGerman bismu,whichhadbeenchangedfromwismu,meaning“white.”
ISOTOPES:Thereareatotalof59radioactiveisotopesforbismuth,ranginginhalf-lives fromafewmillisecondstothousandsofyears.Atonetimeitwasthoughtthattherewas justonestableisotope(Bi-209),butitwaslaterfoundthatBi-209isradioactivewith
ahalf-lifeof19,000,000,000,000,000,000years.Suchalonghalf-lifemeansthatBi- 209hasnotcompletelydisintegratedandisstillfoundinnature,andisthusconsidered stable.Inthiscase,Bi-209makesup100%ofBismuth’snaturalabundance.
ELECTRONCONFIGURATION EnergyLevels/Shells/Electrons Orbitals/Electrons
s2,p6
3-M=18
s2,p6,d10
4-N=32
s2,p6,d10,f14
5-O=18
s2,p6,d10
221 Properties
Guide to the Elements |
Bismuth is the fifth element in the nitrogen group, and its properties are the most metal-like of the five. Elemental bismuth is a heavy, brittle, hard metal that can be polished to a bright gray-white coat with a pinkish hue. It is not found in this state very often because it is more likely to be combined with other metals and minerals, such as tin, lead, iron and cadmium. These are mixtures with low melting points, making them useful in fire-detection devices.
When heated in air, bismuth burns with a blue flame, giving off clouds of its yellow oxide. Bismuth’s melting point is 271.40°C, its boiling point is 1,564°C, and its density is 9.807 g/cm 3 .
Characteristics Bismuth is more resistant to electrical current in its solid state than it is in its liquid form.
Its thermal conductivity is the lowest of all metals, except mercury. Even though it is consid- ered a metal-like element, it is a very poor conductor of heat and electricity.
Bismuth has a characteristic similar to water. It expands when changing from the liquid phase to the solid phase. This factor makes it useful as an alloy in metals that are used to fill molds, given that it will expand to the cast’s dimensions.
AbundanceandSource Bismuth is the 70th most abundant element, and it is widely spread over the Earth’s crust, but
in very small amounts. There are no major concentrated sources. It occurs both in the free elemen- tal state and in several ores. The major ore, bismuthinite (B 2 S 3 ), is found in South America. The United States gets most of its bismuth as a by-product from smelting ores of lead, silver, copper, and gold. It is also recovered from the refining of tin and tungsten ores.
History Bismuth, arsenic, antimony, and zinc were known as metals in the days of alchemy (500
BCE to 1600 CE). Philippus Aureolus Theophrastus bombastus von Hohenheim (1493–1541), better known as Paracelsus, mentioned bismuth as well as otherthen-known metals in his writings. In the middle of the fifteenth century, bismuth was described by a German monk, Basilus Valentinus (fl. 1640). He called it wismut masse, which is the German term for “white stuff or white mass.” One problem was distinguishing bismuth from lead and tin. Georgius Agricola (1494–1555) worked on this problem at the same time as Paracelsus, but more as
a scientist than as an alchemist. He tentatively separated the metals as bismutum (bismuth), plumbum candidum (tin), and nigrum (lead). Bismuth was not definitively identified as a sepa- rate element until 1659 when Johann Glauber used glass beads to demonstrate the importance of color in flames of different substances when trying to identify them. In 1753 Claude J. Geoffroy (1729–1753) separated bismuth from its ore.
Not much is known of the element’s use until the knowledge of metallurgy developed in the late eighteenth century, when arsenic, antimony, and bismuth were used to form alloys with other metals.
CommonUses Bismuth is used to make the drugs such as Pepto-Bismol for upset stomachs and diarrhea
and in medicine to treat intestinal infections. Bismuth is used in the cosmetics industry to provide the “shine” for lipsticks, eye shadow, and other products.
222 | The History and Use of Our Earth’s Chemical Elements
Bismuth is similar to antimony in that it expands from the molten liquid state to the solid state. This property makes it an excellent material to pour into molds and can produce fine details in whatever is being molded, such as metallic printing type and similar fine castings.
ExamplesofCompounds Bismuth has a +3 oxidation state that in some ways limits the type of compounds it
forms. Bismuth chloride (Bi 3+ + 3Cl 1- → BiCl 3 ) reacts with water to produce what is known as “bismuth white” pigment. Bismuth antimonide (BiSb) is not really a compound but single crystals of the alloy of bis- muth and antimony. The crystals are used as semiconductors in the electronics industry and to produce type for printing presses and low-melting-point electrical fuses.
Bismuth subcarbonate [(BiO) 2 CO 3 ] is used to make other bismuth compounds, cosmetics, enamel, and ceramic glazes. Its major use is as an opaque substance placed in the digestive tract to show up on X-rays. The bismuth blocks X-rays, and thus the physician can see patterns inside the stomach and intestines.
Bismuth subnitrate (BiNO 3 ) is used in the cosmetics industry and to make ceramic and enamel glazes.
Hazards Bismuth is flammable as a powder. The halogen compounds of bismuth are toxic when
inhaled or ingested. Some of the salts of bismuth can cause metallic poisoning in a manner similar to mercury and lead.
At the beginning of the twentieth century, before penicillin, bismuth compounds were used to treat some venereal diseases. However, the treatment was generally unsuccessful.
The Oxygen Group (Oxidizers and Nonmetals): Periods 2 to 6, Group 16 (VIA)