Silver molybdate
Chemical compound
From Wikipedia, the free encyclopedia
Silver molybdate is an inorganic compound with the chemical formula Ag2MoO4. It is a yellow solid that crystallizes in the cubic system and exhibits dimorphism. It is often used in glass.[citation needed]
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3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.033.962 |
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| Ag2MoO4 | |
| Molar mass | 375.67 g/mol |
| Appearance | yellow crystals |
| Density | 6.18 g/cm3, solid |
| Melting point | 483 °C (901 °F; 756 K) |
| slightly soluble | |
| Structure | |
| cubic | |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Structure
Silver molybdate crystals present two types of electronic structure, depending on the pressure conditions to which the crystal is subjected.[1] At room temperature, it exhibits a spinel-type cubic structure, known as β-Ag2MoO4, which is more stable in nature. However, when exposed to high hydrostatic pressure, the tetragonal α-Ag2MoO4 forms as a metastable phase.[2]
Synthesis and properties
α-Ag2MoO4
α-Ag2MoO4 can be prepared by solution-phase precipitation under ambient conditions, using 3-bis(2-pyridyl)pyrazine (dpp) as a doping agent.[3] The pH of the starting solution influences the growth and formation processes of distinct heterostructures (brooms, flowers and rods).[4][5]
β-Ag2MoO4
β-Ag2MoO4 crystals can be prepared by solid-state reaction or oxide mixture at high temperature,[6] melt-quenching,[7] and Czochralski growth.[8]
Additional methods include co-precipitation,[citation needed] microwave-assisted hydrothermal synthesis,[9] a dynamic template route using polymerization of acrylamide assisted templates,[10] and an impregnation/calcination method.[11]
β-Ag2MoO4 microcrystals can be synthesized by precipitation employing polar solvents.[12]
Photocatalytic properties of β–Ag2MoO4 crystals can be improved through hydrothermal processing at different temperatures.[13] The replacement of Ag atoms with Zn to form silver-zinc molybdate [β–(Ag2−2xZnx)MoO4] microcrystals by a sonochemical method also leads to improvements.[14] These crystals are able to degrade rhodamine B and Remazol Brilliant Violet 5R.[13][14]
Ag-Ag2MoO4 composites
Ag-Ag2MoO4 composites can be prepared by microwave-assisted hydrothermal synthesis. These composites present photocatalytic activity for the degradation of rhodamine B under visible light.[15]
Other properties
Ag2MoO4 mixed with graphite acts as a good lubricant for Ni-based composites, improving the tribological properties of the system.[16]