Ammonium dimolybdate

Ammonium dimolybdate
Names
	Other names ADM
Identifiers
CAS Number	27546-07-2;
3D model (JSmol)	Interactive image;
ECHA InfoCard	100.044.092
PubChem CID	21895884;
	InChI InChI=1S/2Mo.H3N.8O/h;;1H3;;;;;;;;/q;;;;;;;4*-1/p+1 Key: UHQWHVHZVHVJFE-UHFFFAOYSA-O;
	SMILES [NH4+].[O-][Mo](=O)(=O)[O-].[O-][Mo](=O)(=O)[O-];
Properties
Chemical formula	H8N2Mo2O7
Appearance	white solid
Density	2.97 g/cm3
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	Infobox references

Ammonium dimolybdate (ADM) is the inorganic compound with the formula (NH₄)₂Mo₂O₇. It is a white, water-soluble solid. ADM is an intermediate in the production of molybdenum compounds from its ores. Roasting typical ore produces crude molybdenum(VI) oxides, which can be extracted into aqueous ammonia, affording ammonium molybdate. Heating solutions of ammonium molybdate gives ADM. Upon heating, solid ammonium dimolybdate decomposes to molybdenum trioxide:^[1]

(NH₄)₂Mo₂O₇ → 2 MoO₃ + 2 NH₃ + H₂O

In terms of its chemical structure, the anion is a polymeric consisting of distorted octahedral Mo centers liked by tetrahedral molybdate centers.^[2] When prepared in the absence of water as its tetrabutylammonium salt, dimolybdate adopts the centrosymmetric structure observed for dichromate.^[3]

References

↑ Roger F. Sebenik et al. (2005). "Molybdenum and Molybdenum Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a16_655.
↑ Armour, A. W.; Drew, M. G. B.; Mitchell, P. C. H. "Crystal and molecular structure and properties of ammonium dimolybdate" Journal of the Chemical Society, Dalton Transactions,1975, p1493-p1496. {{DOI: 10.1039/DT9750001493}}
↑ Day, V. W.; Klemperer, W. G. (1985). "Metal Oxide Chemistry in Solution: The Early Transition Metal Polyoxoanions". Science. 228: 533–541. doi:10.1126/science.228.4699.533.

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[ullmann-1] Roger F. Sebenik et al. (2005). "Molybdenum and Molybdenum Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a16_655.

[2] Armour, A. W.; Drew, M. G. B.; Mitchell, P. C. H. "Crystal and molecular structure and properties of ammonium dimolybdate" Journal of the Chemical Society, Dalton Transactions,1975, p1493-p1496. {{DOI: 10.1039/DT9750001493}}

[3] Day, V. W.; Klemperer, W. G. (1985). "Metal Oxide Chemistry in Solution: The Early Transition Metal Polyoxoanions". Science. 228: 533–541. doi:10.1126/science.228.4699.533.