Thorium dioxide (ThO2), also called thorium(IV) oxide, is a crystalline solid, often white or yellow in color. Also known as thoria, it is produced mainly as a by-product of lanthanide and uranium production.[4] Thorianite is the name of the mineralogical form of thorium dioxide. It is moderately rare and crystallizes in an isometric system. The melting point of thorium oxide is 3300 °C – the highest of all known oxides. Only a few elements (including tungsten and carbon) and a few compounds (including tantalum carbide) have higher melting points.[5] All thorium compounds are radioactive because there are no stable isotopes of thorium.
https://en.wikipedia.org/wiki/Thorium_dioxide
Auerlite is a rare North Carolina mineral variety, remarkably rich in thoria, named after Carl Auer von Welsbach, the inventor of the Welsbach incandescent gas mantle. It is considered to be a phosphorus bearing variety of thorite.[1]
Description[edit]
It was originally described as a hydrous silico-phosphate of thorium, ThO2(SiO2,⅓P2O5)+2H2O, i.e. thorite in which part of the silica is replaced by phosphoric acid. The crystals are tetragonal, lemon-yellow to brown-red in color, and sub-translucent to opaque. The mineral is very brittle; its hardness is 2.5 to 3, and its specific gravity 4.422 to 4.766, the darker crystals having the greatest density.
Analysis gave the following results: —
| H2O | CO2 | SiO2 | P2O5 | ThO2 | Fe2O3 | CaO | MgO | Al2O3 | Total |
| 10.21 | 1.00 | 7.64 | 7.46 | 70.13 | 1.38 | 0.49 | 0.29 | 1.10 | 99.70 |
Locations[edit]
This mineral has hitherto been found at only two places in Henderson County, North Carolina, namely, at the Freeman mine, and on the Price land, 3 miles (4.8 km) to the southwest. At both places it occurs in disintegrated granitic or gneissic rock, intimately associated with zircon crystals, on which it is often seen implanted.
Etymology[edit]
As this mineral was found while mining the zircons necessary to supply the demand caused by the invention of the system of incandescent gas lighting of Carl Auer von Welsbach, the authors of the original description proposed to name it Auerlite in his honour.
https://en.wikipedia.org/wiki/Auerlite
Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is a weak acid with the chemical formula H
3PO
4. The pure compound is a colorless solid.
All three hydrogens are acidic to varying degrees and can be lost from the molecule as H+ ions (protons). When all three H+ ions are removed, the result is an orthophosphate ion PO43−, commonly called "phosphate". Removal of one or two protons gives dihydrogen phosphate ion H
2PO−
4, and the hydrogen phosphateion HPO2−
4, respectively. Orthophosphoric acid also forms esters, called organophosphates.[15]
Phosphoric acid is commonly encountered in chemical laboratories as an 85% aqueous solution, which is a colourless, odourless, and non-volatile syrupy liquid. Although phosphoric acid does not meet the strict definition of a strong acid, the 85% solution can still severely irritate the skin and damage the eyes.
The name "orthophosphoric acid" can be used to distinguish this specific acid from other "phosphoric acids", such as pyrophosphoric acid. Nevertheless, the term "phosphoric acid" often means this specific compound; and that is the current IUPAC nomenclature.
https://en.wikipedia.org/wiki/Phosphoric_acid
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