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Chemical Education Today
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Letters
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More about A Living Periodic Table
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James L. Marshall
Department of Chemistry, University of North Texas, Denton, TX 76203-5070
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September 2000
Vol. 77 No. 9
p. 1119
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| Full Text |
The cover of the August 2000 issue featured mineral samples associated with elements on the left side of the periodic table. Readers may be interested in the following information about the minerals pictured. Detailed information about A Living Periodic Table is in J. Chem. Educ. 2000, 77, 979-983.
- 1 Hydrogen: hydronium jarosite
- Hydronium jarosite is an unusual ionic compound that contains hydronium ions, H3O+. The formula is (H3O)Fe3(SO4) 2(OH)6. On this sample, the compound is the yellow crust on the quartz matrix.
- 3 Lithium: petalite and spodumene
- Lithium was originally discovered in spodumene (LiAlSi2O6, pale greenish, top) and petalite (LiAlSi4O10, white, center). This sample is from the original site, Üto, Sweden, an island near Stockholm.
- 4 Beryllium: emerald
- Beryllium was originally discovered in Siberian emeralds. This sample, from the Ural Mountains, is embedded in schist. Emerald is a gem form of beryl (Al2Be3Si6O18 ).
- 11 Sodium: halite
- Halite (NaCl) crystallizes in cubes and can be found in geological formations where brine has evaporated.
- 12 Magnesium: magnesite
- Magnesite, MgCO3, is the magnesium analog of calcite (limestone, CaCO3) and crystallizes in the same rhombohedral form.
- 19 Potassium: amazonite
- Amazonite is a green form of microcline, KAlSi3O8, a potassium feldspar. Microcline is the most common potassium feldspar, found in granite and other igneous rocks.
- 20 Calcium: calcite
- Calcite (CaCO3), the most common mineral containing calcium, forms rhombohedral crystals.
- 21 Scandium: euxenite
- There is an inclusion of euxenite in this pegmatite sample from Norway (Scandinavia), the original mineral and site of discovery of scandium. Euxenite has a complex composition, (Y,Ca,Ce)(Nb,Ta,Ti)2O6 with occasional traces of scandium and rare earths.
- 22 Titanium: ilmenite
- Titanium was discovered in ilmenite sand, FeTiO3, a slightly magnetic material. This sample of ilmenite crystal is from South Carolina. Ilmenite is a major ore for titanium.
- 23 Vanadium: vanadinite
- Vanadium was discovered in vanadinite, Pb5(VO4)3Cl, from Mexico.
- 24 Chromium: crocoite
- Chromium was discovered in crocoite, PbCrO4, from the Beresov Mine in the Ural Mountains, Russia.
- 37 Rubidium: lepidolite
- Rubidium was first isolated from lepidolite, an attractive lavender mica with the formula K2Li3Al4Si7 O21(OH)3, in which rubidium may replace up to 4% of the potassium. This sample of lepidolite is from the original site in Saxony, Germany, which was the source of rubidium discovered by Robert W. Bunsen.
- 38 Strontium: strontianite
- Strontium was discovered in strontianite, SrCO3, from Strontian, Scotland. The strontianite from this site is characteristically greenish.
- 39 Yttrium: gadolinite
- Yttrium was discovered in gadolinite, Y2FeBe2Si2O10 , collected from Ytterby, Sweden, on the island of Resarö, near Stockholm. This specimen is taken from this famous mine. Laid on its side, the sample reveals that the gadolinite has been laid down in a layer, on a matrix of feldspar and quartzite, which was mined for the ceramic industry in the 1700s.
- 40 Zirconium: zircon
- Zirconium was isolated from zircon, ZrSiO4, which has been known since antiquity. This sample is from Pakistan, possibly in the general area of the original site of discoveries.
- 41 Niobium: columbite
- Niobium was originally discovered in columbite (FeNb2O6) from Connecticut. This sample, from the original site, shows a dark columbite crystal in a light-colored pegmatite. Chemically confused with tantalum for years, "columbium" was renamed "niobium" by European chemists.
- 42 Molybdenum: molybdenite
- Molybdenite (MoS2) was confused for centuries with both lead (Pb) and graphite, and frequently the same name plumbago was indiscriminately applied to all.
- 55 Cesium: pollucite
- Cesium was discovered in Dürkheim, Germany, spring water. Today the main source of cesium is pollucite, Cs2Na2Al2Si4 O12·H2O.
- 56 Barium: barite roses
- Barite, BaSO4, can take many forms, such as "roses" from Oklahoma.
- 57 Lanthanum: cerite
- This sample of cerite was taken from the famous Bastnäs Mine, Ridarhyttan, Sweden, where cerium was discovered. The formula for cerite is (Ce,RE,Ca)10Fe(SiO4)6 (SiO3OH)(OH)3, where RE = rare earths. Lanthanum was discovered as an impurity in cerium. This sample of cerium held the incredibly high concentration of 12% lanthanum.
- 72 Hafnium: zircon
- With the same atomic size as zirconium, hafnium is frequently found admixed. In this sample of alvite, a type of zircon (Zr,Hf)SiO4, hafnium has replaced 10% of the zirconium.
- 73 Tantalum: yttrotantalite
- This yttrotantalate sample, YTaO4, was found in the famous Ytterby Mine from which tantalum was discovered.
- 74 Tungsten: wolframite
- This sample of wolframite, FeWO4, from Zinnwald, Bohemia, represents the mineral and the site from which metallic tungsten was first isolated.
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| More Information |
 Citation |
Marshall, James L. J. Chem. Educ. 2000 77 1119.
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Keywords |
Demonstrations; History / Philosophy; Introductory / High School Chemistry; Main-Group Elements; Periodicity / Periodic Table; Public Understanding; Transition Elements
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History |
Created:
Last Updated: |
August 29, 2000
June 22, 2005
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