Molybdate

Last updated November 03, 2023

In chemistry, a molybdate is a compound containing an oxyanion with molybdenum in its highest oxidation state of 6: O⁻−Mo(=O)₂−O⁻. Molybdenum can form a very large range of such oxyanions, which can be discrete structures or polymeric extended structures, although the latter are only found in the solid state. The larger oxyanions are members of group of compounds termed polyoxometalates , and because they contain only one type of metal atom are often called isopolymetalates.^[1] The discrete molybdenum oxyanions range in size from the simplest MoO²⁻
₄, found in potassium molybdate up to extremely large structures found in isopoly-molybdenum blues that contain for example 154 Mo atoms. The behaviour of molybdenum is different from the other elements in group 6. Chromium only forms the chromates, CrO²⁻
₄, Cr^₂O²⁻
₇, Cr^₃O²⁻
₁₀ and Cr^₄O²⁻
₁₃ ions which are all based on tetrahedral chromium. Tungsten is similar to molybdenum and forms many tungstates containing 6 coordinate tungsten.^[2]

Examples of molybdate anions

Examples of molybdate oxyanions are:

MoO²⁻
₄, in e.g. Na₂MoO₄ and the mineral powellite, CaMoO₄;
Mo^₂O²⁻
₇, as hydrated ammonium dimolybdate. The anhydrous tetrabutylammonium salt of Mo^₂O²⁻
₇ is also known;^[3]
Mo^₃O²⁻
₁₀ in the ethylenediamine salt;^[4]
Mo^₄O²⁻
₁₃ in the potassium salt;^[5]
Mo^₅O²⁻
₁₆ in the anilinium (C^₆H^₅NH⁺
₃) salt;^[6]
Mo^₆O²⁻
₁₉(hexa-molybdate) in the tetramethylammonium salt;^[7]
Mo^₇O⁶⁻
₂₄ in ammonium heptamolybdate, (NH₄)₆Mo₇O₂₄·4H₂O;^[8]
Mo^₈O⁴⁻
₂₆ in trimethylammonium salt.^[1]

The naming of molybdates generally follows the convention of a prefix to show the number of Mo atoms present. For example, dimolybdate for 2 molybdenum atoms; trimolybdate for 3 molybdenum atoms, etc.. Sometimes the oxidation state is added as a suffix, such as in pentamolybdate(VI). The heptamolybdate ion, Mo^₇O⁶⁻
₂₄, is often called "paramolybdate".

Structure of molybdate anions

The smaller anions, MoO²⁻
₄ and Mo^₂O²⁻
₇ feature tetrahedral centres. In MoO²⁻
₄ the four oxygens are equivalent as in sulfate and chromate, with equal bond lengths and angles. Mo^₂O²⁻
₇ can be considered to be two tetrahedra sharing a corner, i.e. with a single bridging O atom.^[1] In the larger anions molybdenum is generally, but not exclusively, 6 coordinate with edges or vertices of the MoO₆ octahedra being shared. The octahedra are distorted, typical M-O bond lengths are:

in terminal non bridging M–O approximately 1.7 Å
in bridging M–O–M units approximately 1.9 Å

The Mo^₈O⁴⁻
₂₆ anion contains both octahedral and tetrahedral molybdenum and can be isolated in 2 isomeric forms, alpha and beta.^[2]

The hexamolybdate image below shows the coordination polyhedra. The space filling model of the heptamolybdate image shows the close packed nature of the oxygen atoms in the structure. The oxide ion has an ionic radius of 1.40 Å, molybdenum(VI) is much smaller, 0.59 Å.^[1] There are strong similarities between the structures of the molybdates and the molybdenum oxides, (MoO₃, MoO₂ and the "crystallographic shear" oxides, Mo₉O₂₆ and Mo₁₀O₂₉) whose structures all contain close packed oxide ions.^[9]

(a) Hexamolybdate [Mo₆O₁₉]²⁻ (b) Heptamolybdate [Mo₇O₂₄]⁶⁻
Ball and stick model of heptamolybdate
Heptamolybdate with space filling oxygen atoms

Equilibria in aqueous solution

When MoO₃, molybdenum trioxide is dissolved in alkali solution the simple MoO2−4 anion is produced:

{\ce {MoO3 + 2 NaOH -> Na2MoO4 + H2O}}

As the pH is lowered, condensations ensue, with loss of water and the formation of Mo–O–Mo linkages. The stoichiometry leading to hexa-, hepta-, and octamolybdates are shown:^[1]^[10]

{\ce {6 [MoO4]^2- + 10 HCl -> [Mo6O19]^2- + 10 Cl- + 5 H2O}}

{\ce {7 MoO4^2- + 8 H+ -> Mo7O24^6- + 4 H2O}}

^[2]

{\ce {Mo7O24^6- + HMoO4^- + 3 H+ -> Mo8O26^4- + 2 H2O}}

^[2]

Peroxomolybdates

Many peroxomolybdates are known. They tend to form upon treatment of molybdate salts with hydrogen peroxide. Notable is the monomer–dimer equilibrium:

{\ce {[Mo2O3(O2)2(H2O)2]^2- <=> [Mo2O3(O2)4(H2O)2]^2-}}

Also known but unstable is [Mo(O₂)₄]²⁻ (see potassium tetraperoxochromate(V)). Some related compounds find use as oxidants in organic synthesis.^[11]

Tetrathiomolybdate

The red tetrathiomolybdate anion results when molybdate solutions are treated with hydrogen sulfide:

{\ce {[NH4]2[MoO4] + 4 H2S -> [NH4]2[MoS4] + 4 H2O}}

Like molybdate itself, MoS2−4 undergoes condensation in the presence of acids, but these condensations are accompanied by redox processes.

Industrial uses

Catalysis

Molybdates are widely used in catalysis. In terms of scale, the largest consumer of molybdate is as a precursor to catalysts for hydrodesulfurization, the process by which sulfur is removed from petroleum. Bismuth molybdates, nominally of the composition Bi₉PMo₁₂O₅₂, catalyzes ammoxidation of propylene to acrylonitrile. Ferric molybdates are used industrially to catalyze the oxidation of methanol to formaldehyde.^[12]

Corrosion inhibitors

Sodium molybdate has been used in industrial water treatment as a corrosion inhibitor. It was initially thought that it would be a good replacement for chromate, when chromate was banned for toxicity. However, molybdate requires high concentrations when used alone, therefore complementary corrosion inhibitors are generally added,^[13] and is mainly used in high temperature closed-loop cooling circuits.^[14] According to an experimental study, Molybdate has been reported as an efficient biocide against microbiologically induced corrosion (MIC), where adding 1.5 mM of Molybdate/day resulted in a 50% decrease in the corrosion rate.^[15]

Supercapacitors

Molybdates (especially FeMoO₄, Fe₂(MoO₄)₃, NiMoO₄, CoMoO₄ and MnMoO₄) have been used as anode or cathode materials in aqueous capacitors.^[16]^[17]^[18]^[19] Due to pseudocapacitive charge storage, specific capacitance up to 1500 F g⁻¹ has been observed.^[17]

Medicine

Radioactive molybdenum-99 in the form of molybdate is used as the parent isotope in technetium-99m generators for nuclear medicine imaging.^[20]

Other

Nitrogen fixation requires molybdoenzymes in legumes (e.g., soybeans, acacia, etc.). For this reason, fertilizers often contain small amounts of molybdate salts. Coverage is typically less than a kilogram per acre.^[12]

Molybdate chrome pigments are speciality but commercially available pigments.^[12] Molybdate (usually in the form of potassium molybdate) is also used in the analytical colorimetric testing for the concentration of silica in solution, called the molybdenum blue method.^[21] Additionally, it is used in the colorimetric determination of phosphate quantity in association with the dye malachite green.

Collectible molybdate

Molybdate crystals as collected by gem enthusiasts with the world's best samples of crystalized Molybdate coming from Madawaska Mine.^[22]

Related Research Articles

<span class="mw-page-title-main">Oxide</span> Chemical compound where oxygen atoms are combined with atoms of other elements

An oxide is a chemical compound containing at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O^2– ion with oxygen in the oxidation state of −2. Most of the Earth's crust consists of oxides. Even materials considered pure elements often develop an oxide coating. For example, aluminium foil develops a thin skin of Al₂O₃ that protects the foil from further oxidation.

<span class="mw-page-title-main">Osmium tetroxide</span> Chemical compound

Osmium tetroxide (also osmium(VIII) oxide) is the chemical compound with the formula OsO₄. The compound is noteworthy for its many uses, despite its toxicity and the rarity of osmium. It also has a number of unusual properties, one being that the solid is volatile. The compound is colourless, but most samples appear yellow. This is most likely due to the presence of the impurity OsO₂, which is yellow-brown in colour. In biology, its property of binding to lipids has made it a widely-used stain in electron microscopy.

An oxyanion, or oxoanion, is an ion with the generic formula A^_xO^z−
_y. Oxyanions are formed by a large majority of the chemical elements. The formulae of simple oxyanions are determined by the octet rule. The corresponding oxyacid of an oxyanion is the compound H^_zA^_xO^_y. The structures of condensed oxyanions can be rationalized in terms of AO_n polyhedral units with sharing of corners or edges between polyhedra. The oxyanions adenosine monophosphate (AMP), adenosine diphosphate (ADP) and adenosine triphosphate (ATP) are important in biology.

<span class="mw-page-title-main">Chromate and dichromate</span> Chromium(VI) anions

Chromate salts contain the chromate anion, CrO²⁻
₄. Dichromate salts contain the dichromate anion, Cr^₂O²⁻
₇. They are oxyanions of chromium in the +6 oxidation state and are moderately strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible.

In chemistry, a polyoxometalate is a polyatomic ion, usually an anion, that consists of three or more transition metal oxyanions linked together by shared oxygen atoms to form closed 3-dimensional frameworks. The metal atoms are usually group 6 or less commonly group 5 and group 7 transition metals in their high oxidation states. Polyoxometalates are often colorless, orange or red diamagnetic anions. Two broad families are recognized, isopolymetalates, composed of only one kind of metal and oxide, and heteropolymetalates, composed of one metal, oxide, and a main group oxyanion. Many exceptions to these general statements exist.

<span class="mw-page-title-main">Permanganate</span> Chemical compound

A permanganate is a chemical compound with the manganate(VII) ion, MnO⁻
₄, the conjugate base of permanganic acid. Because the manganese atom has a +7 oxidation state, the permanganate(VII) ion is a strong oxidising agent. The ion is a transition metal ion with a tetrahedral structure. Permanganate solutions are purple in colour and are stable in neutral or slightly alkaline media. The exact chemical reaction depends on the carbon-containing reactants present and the oxidant used. For example, trichloroethane (C₂H₃Cl₃) is oxidised by permanganate ions to form carbon dioxide (CO₂), manganese dioxide (MnO₂), hydrogen ions (H⁺), and chloride ions (Cl⁻).

Molybdenum trioxide describes a family of inorganic compounds with the formula MoO₃(H₂O)_n where n = 0, 1, 2. These compounds are produced on the largest scale of any molybdenum compound. The anhydrous oxide is a precursor to molybdenum metal, an important alloying agent. It is also an important industrial catalyst. It is a yellow solid, although impure samples can appear blue or green.

<span class="mw-page-title-main">Manganate</span> Chemical compound

In inorganic nomenclature, a manganate is any negatively charged molecular entity with manganese as the central atom. However, the name is usually used to refer to the tetraoxidomanganate(2−) anion, MnO²⁻
₄, also known as manganate(VI) because it contains manganese in the +6 oxidation state. Manganates are the only known manganese(VI) compounds.

In chemistry, an aluminate is a compound containing an oxyanion of aluminium, such as sodium aluminate. In the naming of inorganic compounds, it is a suffix that indicates a polyatomic anion with a central aluminium atom.

<span class="mw-page-title-main">Tellurate</span> Compound containing an oxyanion of tellurium

In chemistry tellurate is a compound containing an oxyanion of tellurium where tellurium has an oxidation number of +6. In the naming of inorganic compounds it is a suffix that indicates a polyatomic anion with a central tellurium atom.

Sodium molybdate, Na₂MoO₄, is useful as a source of molybdenum. This white, crystalline salt is often found as the dihydrate, Na₂MoO₄·2H₂O.

In chemical nomenclature, the IUPAC nomenclature of inorganic chemistry is a systematic method of naming inorganic chemical compounds, as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in Nomenclature of Inorganic Chemistry. Ideally, every inorganic compound should have a name from which an unambiguous formula can be determined. There is also an IUPAC nomenclature of organic chemistry.

In chemistry, hypomanganate, also called manganate(V) or tetraoxidomanganate(3−), is a trivalent anion (negative ion) composed of manganese and oxygen, with formula MnO³⁻
₄.

Chromium is a member of group 6, of the transition metals. The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium are rare, but do nevertheless occasionally exist.

Ammonium heptamolybdate is the inorganic compound whose chemical formula is (NH₄)₆Mo₇O₂₄, normally encountered as the tetrahydrate. A dihydrate is also known. It is a colorless solid, often referred to as ammonium paramolybdate or simply as ammonium molybdate, although "ammonium molybdate" can also refer to ammonium orthomolybdate, (NH₄)₂MoO₄, and several other compounds. It is one of the more common molybdenum compounds.

Molybdenum blue is a term applied to:

A disulfite, commonly known as metabisulfite or pyrosulfite, is a chemical compound containing the ion S^₂O²⁻
₅. It is a colorless dianion that is primarily marketed in the form of sodium metabisulfite or potassium metabisulfite. When dissolved in water, these salts release the hydrogensulfite HSO⁻
₃ anion. These salts act equivalently to sodium hydrogensulfite or potassium hydrogensulfite.

A transition metal oxo complex is a coordination complex containing an oxo ligand. Formally O^2-, an oxo ligand can be bound to one or more metal centers, i.e. it can exist as a terminal or (most commonly) as bridging ligands (Fig. 1). Oxo ligands stabilize high oxidation states of a metal. They are also found in several metalloproteins, for example in molybdenum cofactors and in many iron-containing enzymes. One of the earliest synthetic compounds to incorporate an oxo ligand is potassium ferrate (K₂FeO₄), which was likely prepared by Georg E. Stahl in 1702.

Manganese(II) molybdate is an inorganic compound with the chemical formula MnMoO₄. α-MnMoO₄ has a monoclinic crystal structure. It is also antiferromagnetic at low temperatures.

Potassium hypochromate is a chemical compound with the formula K₃CrO₄ with the unusual Cr⁵⁺ ion. This compound is unstable in water but stable in alkaline solution and was found to have a similar crystal structure to potassium hypomanganate.

References

1 2 3 4 5 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
1 2 3 4 Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5
↑ V. W. Day; M. F. Fredrich; W. G. Klemperer; W. Shum (1977). "Synthesis and characterization of the dimolybdate ion, Mo^₂O²⁻
₇". Journal of the American Chemical Society. 99 (18): 6146. doi:10.1021/ja00460a074.
↑ Guillou N.; Ferey G. (August 1997). "Hydrothermal Synthesis and Crystal Structure of Anhydrous Ethylenediamine Trimolybdate (C^₂H^₁₀N^₂)[Mo^₃O^₁₀]". Journal of Solid State Chemistry. 132 (1): 224–227(4). Bibcode:1997JSSCh.132..224G. doi:10.1006/jssc.1997.7502.
↑ B. M. Gatehouse; P. Leverett (1971). "Crystal structure of potassium tetramolybdate, K^₂Mo^₄O^₁₃, and its relationship to the structures of other univalent metal polymolybdates". J. Chem. Soc. A: 2107–2112. doi:10.1039/J19710002107.
↑ W. Lasocha; H. Schenk (1997). "Crystal Structure of Anilinium Pentamolybdate from Powder Diffraction Data. The Solution of the Crystal Structure by Direct Methods Package POWSIM". J. Appl. Crystallogr. 30 (6): 909–913. doi:10.1107/S0021889897003105.
↑ S. Ghammami (2003). "The crystal and molecular structure of bis(tetramethylammonium) hexamolybdate(VI)". Crystal Research and Technology. 38 (913): 913–917. doi:10.1002/crat.200310112. S2CID 95078211.
↑ Howard T. Evans jr.; Bryan M. Gatehouse; Peter Leverett (1975). "Crystal structure of the heptamolybdate(VI)(paramolybdate) ion, [Mo₇O₂₄]⁶⁻, in the ammonium and potassium tetrahydrate salts". J. Chem. Soc., Dalton Trans. (6): 505–514. doi:10.1039/DT9750000505.
↑ "Oxides: solid state chemistry" W.H. McCarroll, Encyclopedia of Inorganic Chemistry Ed. R. Bruce King, John Wiley and Sons (1994) ISBN 0-471-93620-0
↑ Klemperer, W. G. (1990). "Tetrabutylammonium Isopolyoxometalates". Inorganic Syntheses. Inorganic Syntheses. Vol. 27. pp. 74–85. doi:10.1002/9780470132586.ch15. ISBN 9780470132586.
↑ Dickman, Michael H.; Pope, Michael T. (1994). "Peroxo and Superoxo Complexes of Chromium, Molybdenum, and Tungsten". Chem. Rev. 94 (3): 569–584. doi:10.1021/cr00027a002.
1 2 3 Roger F. Sebenik et al. "Molybdenum and Molybdenum Compounds" in Ullmann's Encyclopedia of Chemical Technology 2005; Wiley-VCH, Weinheim. doi : 10.1002/14356007.a16_655
↑ "Open Recirculating Cooling Systems - GE Water". gewater.com.
↑ "Closed Recirculating Cooling Systems - GE Water". gewater.com.
↑ "Microbiologically Influenced Corrosion in the Upstream Oil and Gas Industry".
↑ Purushothaman, K. K.; Cuba, M.; Muralidharan, G. (2012-11-01). "Supercapacitor behavior of α-MnMoO4 nanorods on different electrolytes". Materials Research Bulletin. 47 (11): 3348–3351. doi:10.1016/j.materresbull.2012.07.027.
1 2 Senthilkumar, Baskar; Sankar, Kalimuthu Vijaya; Selvan, Ramakrishnan Kalai; Danielle, Meyrick; Manickam, Minakshi (2012-12-05). "Nano α-NiMoO4as a new electrode for electrochemical supercapacitors". RSC Adv. 3 (2): 352–357. doi:10.1039/c2ra22743f. ISSN 2046-2069.
↑ Cai, Daoping; Wang, Dandan; Liu, Bin; Wang, Yanrong; Liu, Yuan; Wang, Lingling; Li, Han; Huang, Hui; Li, Qiuhong (2013-12-26). "Comparison of the Electrochemical Performance of NiMoO4 Nanorods and Hierarchical Nanospheres for Supercapacitor Applications". ACS Applied Materials & Interfaces. 5 (24): 12905–12910. doi:10.1021/am403444v. ISSN 1944-8244. PMID 24274769.
↑ Xia, Xifeng; Lei, Wu; Hao, Qingli; Wang, Wenjuan; Wang, Xin (2013-06-01). "One-step synthesis of CoMoO4/graphene composites with enhanced electrochemical properties for supercapacitors". Electrochimica Acta. 99: 253–261. doi:10.1016/j.electacta.2013.03.131.
↑ National Research Council (US) Committee on Medical Isotope Production Without Highly Enriched Uranium. (2009). "Molybdenum-99/Technetium-99m Production and Use". Medical Isotope Production without Highly Enriched Uranium. Washington DC: National Academies Press.
↑ "ASTM D7126 - 15 Standard Test Method for On-Line Colorimetric Measurement of Silica". astm.org.
↑ McDougall, Raymond (2019-09-03). "Mineral Highlights from the Bancroft Area, Ontario, Canada". Rocks & Minerals. 94 (5): 408–419. doi:10.1080/00357529.2019.1619134. ISSN 0035-7529. S2CID 201298402.

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[greenwood-1] 1 2 3 4 5 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.

[cotton-2] 1 2 3 4 Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5

[3] V. W. Day; M. F. Fredrich; W. G. Klemperer; W. Shum (1977). "Synthesis and characterization of the dimolybdate ion, Mo^₂O²⁻
₇". Journal of the American Chemical Society. 99 (18): 6146. doi:10.1021/ja00460a074.

[4] Guillou N.; Ferey G. (August 1997). "Hydrothermal Synthesis and Crystal Structure of Anhydrous Ethylenediamine Trimolybdate (C^₂H^₁₀N^₂)[Mo^₃O^₁₀]". Journal of Solid State Chemistry. 132 (1): 224–227(4). Bibcode:1997JSSCh.132..224G. doi:10.1006/jssc.1997.7502.

[5] B. M. Gatehouse; P. Leverett (1971). "Crystal structure of potassium tetramolybdate, K^₂Mo^₄O^₁₃, and its relationship to the structures of other univalent metal polymolybdates". J. Chem. Soc. A: 2107–2112. doi:10.1039/J19710002107.

[6] W. Lasocha; H. Schenk (1997). "Crystal Structure of Anilinium Pentamolybdate from Powder Diffraction Data. The Solution of the Crystal Structure by Direct Methods Package POWSIM". J. Appl. Crystallogr. 30 (6): 909–913. doi:10.1107/S0021889897003105.

[7] S. Ghammami (2003). "The crystal and molecular structure of bis(tetramethylammonium) hexamolybdate(VI)". Crystal Research and Technology. 38 (913): 913–917. doi:10.1002/crat.200310112. S2CID 95078211.

[8] Howard T. Evans jr.; Bryan M. Gatehouse; Peter Leverett (1975). "Crystal structure of the heptamolybdate(VI)(paramolybdate) ion, [Mo₇O₂₄]⁶⁻, in the ammonium and potassium tetrahydrate salts". J. Chem. Soc., Dalton Trans. (6): 505–514. doi:10.1039/DT9750000505.

[9] "Oxides: solid state chemistry" W.H. McCarroll, Encyclopedia of Inorganic Chemistry Ed. R. Bruce King, John Wiley and Sons (1994) ISBN 0-471-93620-0

[wgk-10] Klemperer, W. G. (1990). "Tetrabutylammonium Isopolyoxometalates". Inorganic Syntheses. Inorganic Syntheses. Vol. 27. pp. 74–85. doi:10.1002/9780470132586.ch15. ISBN 9780470132586.

[11] Dickman, Michael H.; Pope, Michael T. (1994). "Peroxo and Superoxo Complexes of Chromium, Molybdenum, and Tungsten". Chem. Rev. 94 (3): 569–584. doi:10.1021/cr00027a002.

[ullmann-12] 1 2 3 Roger F. Sebenik et al. "Molybdenum and Molybdenum Compounds" in Ullmann's Encyclopedia of Chemical Technology 2005; Wiley-VCH, Weinheim. doi : 10.1002/14356007.a16_655

[13] "Open Recirculating Cooling Systems - GE Water". gewater.com.

[14] "Closed Recirculating Cooling Systems - GE Water". gewater.com.

[15] "Microbiologically Influenced Corrosion in the Upstream Oil and Gas Industry".

[16] Purushothaman, K. K.; Cuba, M.; Muralidharan, G. (2012-11-01). "Supercapacitor behavior of α-MnMoO4 nanorods on different electrolytes". Materials Research Bulletin. 47 (11): 3348–3351. doi:10.1016/j.materresbull.2012.07.027.

[:0-17] 1 2 Senthilkumar, Baskar; Sankar, Kalimuthu Vijaya; Selvan, Ramakrishnan Kalai; Danielle, Meyrick; Manickam, Minakshi (2012-12-05). "Nano α-NiMoO4as a new electrode for electrochemical supercapacitors". RSC Adv. 3 (2): 352–357. doi:10.1039/c2ra22743f. ISSN 2046-2069.

[18] Cai, Daoping; Wang, Dandan; Liu, Bin; Wang, Yanrong; Liu, Yuan; Wang, Lingling; Li, Han; Huang, Hui; Li, Qiuhong (2013-12-26). "Comparison of the Electrochemical Performance of NiMoO4 Nanorods and Hierarchical Nanospheres for Supercapacitor Applications". ACS Applied Materials & Interfaces. 5 (24): 12905–12910. doi:10.1021/am403444v. ISSN 1944-8244. PMID 24274769.

[19] Xia, Xifeng; Lei, Wu; Hao, Qingli; Wang, Wenjuan; Wang, Xin (2013-06-01). "One-step synthesis of CoMoO4/graphene composites with enhanced electrochemical properties for supercapacitors". Electrochimica Acta. 99: 253–261. doi:10.1016/j.electacta.2013.03.131.

[20] National Research Council (US) Committee on Medical Isotope Production Without Highly Enriched Uranium. (2009). "Molybdenum-99/Technetium-99m Production and Use". Medical Isotope Production without Highly Enriched Uranium. Washington DC: National Academies Press.

[21] "ASTM D7126 - 15 Standard Test Method for On-Line Colorimetric Measurement of Silica". astm.org.

[22] McDougall, Raymond (2019-09-03). "Mineral Highlights from the Bancroft Area, Ontario, Canada". Rocks & Minerals. 94 (5): 408–419. doi:10.1080/00357529.2019.1619134. ISSN 0035-7529. S2CID 201298402.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[22]