Thorium oxalate

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Thorium oxalate
Th(C2O4)2(H2O)4 (249614).png
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EC Number
  • 218-038-3
PubChem CID
Molar mass 408.07 g/mol
444.114 g/mol (dihydrate)
Density 4.637 g/cm3 (anhydrous)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Thorium oxalate is the inorganic compound with the formula Th(C2O4)2(H2O)4. It is a white insoluble solid prepared by the reaction of thorium(IV) salts with an oxalic acid. [1] The material is a coordination polymer. Each Th(IV) center is bound to 10 oxygen centers: eight provided by the bridging oxalates and two by a pair of aquo ligands. Two additional water of hydration are observed in the lattice. [2]

The solubility product (Ksp) of thorium oxalate is 5.01 × 10−25 [3] Density of anhydrous thorium oxalate is 4.637 g/cm3.

Related Research Articles

The actinoid series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The actinoid series derives its name from the first element in the series, actinium. The informal chemical symbol An is used in general discussions of actinoid chemistry to refer to any actinoid.

Protactinium Chemical element with atomic number 91

Protactinium is a chemical element with the symbol Pa and atomic number 91. It is a dense, silvery-gray actinide metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds in which protactinium is usually present in the oxidation state +5, but it can also assume +4 and even +3 or +2 states. Concentrations of protactinium in the Earth's crust are typically a few parts per trillion, but may reach up to a few parts per million in some uraninite ore deposits. Because of its scarcity, high radioactivity and high toxicity, there are currently no uses for protactinium outside scientific research, and for this purpose, protactinium is mostly extracted from spent nuclear fuel.

Thorium Chemical element with atomic number 90

Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately hard, malleable, and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided.

Terbium Chemical element with atomic number 65

Terbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable, ductile, and soft enough to be cut with a knife. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, evolving hydrogen gas. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime, and euxenite.

Praseodymium Chemical element with atomic number 59

Praseodymium is a chemical element with the symbol Pr and atomic number 59. It is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. Praseodymium is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.

Oxalic acid The simplest dicarboxylic acid

Oxalic acid is an organic compound with the formula C2H2O4. It is a white crystalline solid that forms a colorless solution in water. Its condensed formula is HOOCCOOH, reflecting its classification as the simplest dicarboxylic acid.


Oxalate (IUPAC: ethanedioate) is the dianion with the formula C
, also written (COO)2−
. Either name is often used for derivatives, such as salts of oxalic acid, for example sodium oxalate Na2C2O4, or dimethyl oxalate ((CH3)2C2O4). Oxalate also forms coordination compounds where it is sometimes abbreviated as ox.

Thorium dioxide Chemical compound

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. 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. All thorium compounds are radioactive because there are no stable isotopes of thorium.

Holmium(III) oxide

Holmium(III) oxide, or holmium oxide is a chemical compound of a rare-earth element holmium and oxygen with the formula Ho2O3. Together with dysprosium(III) oxide (Dy2O3), holmium oxide is one of the most powerfully paramagnetic substances known. The oxide, also called holmia, occurs as a component of the related erbium oxide mineral called erbia. Typically, the oxides of the trivalent lanthanides coexist in nature, and separation of these components requires specialized methods. Holmium oxide is used in making specialty colored glasses. Glass containing holmium oxide and holmium oxide solutions have a series of sharp optical absorption peaks in the visible spectral range. They are therefore traditionally used as a convenient calibration standard for optical spectrophotometers.

Uranium(IV) sulfate (U(SO4)2) is a water-soluble salt of uranium. It is a very toxic compound. Uranium sulfate minerals commonly are widespread around uranium bearing mine sites, where they usually form during the evaporation of acid sulfate-rich mine tailings which have been leached by oxygen-bearing waters. Uranium sulfate is a transitional compound in the production of uranium hexafluoride. It was also used to fuel aqueous homogeneous reactors.

Americium dioxide (AmO2) is a black compound of americium. In the solid state AmO2 adopts the fluorite, CaF2 structure. It is used as a source of alpha particles.

Thorium(IV) chloride

Thorium(IV) chloride (ThCl4) is an inorganic chemical compound. In addition to the anhydrous ThCl4, two hydrates have been reported: ThCl4(H2O)4 and ThCl4(H2O)8. These hygroscopic salts are water-soluble and white, at room temperature. Similar to other thorium complexes thorium(IV) chloride has a high melting point 770 °C (1,418 °F) and a boiling point of 921 °C (1,690 °F). Like all the other actinides, thorium is radioactive and has sometimes been used in the production of nuclear energy. Thorium(IV) chloride does not appear naturally.

Organoactinide chemistry

Organoactinide chemistry is the science exploring the properties, structure and reactivity of organoactinide compounds, which are organometallic compounds containing a carbon to actinide chemical bond.

Neptunium(IV) oxide

Neptunium(IV) oxide, or neptunium dioxide, is a radioactive, olive green cubic crystalline solid with the formula NpO2. It is a common product of plutonium fission, and emits both α- and γ-particles.

Oxalic anhydride

Oxalic anhydride or ethanedioic anhydride, also called oxiranedione, is a hypothetical organic compound with the formula C2O3, which can be viewed as the anhydride of oxalic acid or the two-fold ketone of ethylene oxide. It is an oxide of carbon (an oxocarbon).

Ferric oxalate

Ferric oxalate, also known as iron(III) oxalate, is a chemical compound composed of ferric ions and oxalate ligands; it may also be regarded as the ferric salt of oxalic acid. The anhydrous material is pale yellow; however, it may be hydrated to form several hydrates, such as potassium ferrioxalate, or Fe
 • 6H2O, which is bright green in colour.

Actinide chemistry

Actinide chemistry is one of the main branches of nuclear chemistry that investigates the processes and molecular systems of the actinides. The actinides derive their name from the group 3 element actinium. The informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide. All but one of the actinides are f-block elements, corresponding to the filling of the 5f electron shell; lawrencium, a d-block element, is also generally considered an actinide. In comparison with the lanthanides, also mostly f-block elements, the actinides show much more variable valence. The actinide series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium.

Thorium(IV) nitrate

Thorium(IV) nitrate is a chemical compound with the formula Th(NO3)4. A white solid in its anhydrous form, it can form tetra- and pentahydrates. As a salt of thorium it is weakly radioactive.

Americium(III) hydroxide is a radioactive inorganic compound with the chemical formula Am(OH)3. It consists of one americium atom and three hydroxide groups. It was first discovered in 1944, closely related to the Manhattan Project. However, these results were confidential and were only released to the public in 1945. It was the first isolated sample of americium, and the first americium compound discovered.

Uranyl oxalate

Uranyl oxalate (UO2C2O4) is a pale yellow powdered uranyl compound. It is often encountered in industrial nuclear processes at both the front and back-end of the nuclear fuel cycle. Due to its hygroscopicity, uranyl oxalate rarely exists in the dehydrated state and is usually instead found in the trihydrate form (UO2C2O4·3H2O) at room temperature. At room temperature, the powder exhibits a monoclinic crystal structure in the P21/c space group.


  1. Enver Oktay, Ahmet Yayli (2001) Physical properties of thorium oxalate powders and their influence on the thermal decomposition Journal of Nuclear Materials Volume 288, Issue 1, January 2001, Pages 76–82
  2. Ziegelgruber, Kate L.; Knope, Karah E.; Frisch, Mark; Cahill, Christopher L. (2008). "Hydrothermal Chemistry of Th(IV) with Aromatic dicarboxylates: New Framework Compounds and in Situ Ligand Syntheses". Journal of Solid State Chemistry. 181 (2): 373–381. Bibcode:2008JSSCh.181..373Z. doi:10.1016/j.jssc.2007.12.008.
  3. Taishi Kobayashi, Takayuki Sasaki, Ikuji Takagi, Hirotake Moriyama (2009) Solubility of Thorium(IV) in the Presence of Oxalic and Malonic Acids Journal of Nuclear Science and Technology, Vol. 46, No. 11, p. 1085–1090