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Script assisted update of identifiers from ChemSpider, CommonChemistry and FDA for the Chem/Drugbox validation project - Updated: StdInChI StdInChIKey.
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Updating {{chembox}} (no changed fields - added verified revid - updated 'StdInChI_Ref', 'StdInChIKey_Ref') per Chem/Drugbox validation (report errors or
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{{chembox
{{chembox
| verifiedrevid = 395563081
| verifiedrevid = 399508834
| ImageFile = Heptamolybdenan amonný.JPG
| ImageFile = Heptamolybdenan amonný.JPG
| ImageSize =
| ImageSize =
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| InChIKey = QGAVSDVURUSLQK-UHFFFAOYAC
| InChIKey = QGAVSDVURUSLQK-UHFFFAOYAC
| SMILES = [Mo].[Mo].[Mo].[Mo].[Mo].[Mo].[Mo].O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.N.N.N.N.N.N
| SMILES = [Mo].[Mo].[Mo].[Mo].[Mo].[Mo].[Mo].O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.N.N.N.N.N.N
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/7Mo.6H3N.24H2O/h;;;;;;;6*1H3;24*1H2
| StdInChI = 1S/7Mo.6H3N.24H2O/h;;;;;;;6*1H3;24*1H2
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = QGAVSDVURUSLQK-UHFFFAOYSA-N
| StdInChIKey = QGAVSDVURUSLQK-UHFFFAOYSA-N
| CASNo = 12027-67-7
| CASNo = 12027-67-7

Revision as of 12:50, 29 November 2010

Ammonium heptamolybdate
Names
IUPAC name
Ammonium docosaoxoheptamolybdate(6–)
Other names
Ammonium molybdate
Ammonium paramolybdate
(see text)
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.553 Edit this at Wikidata
EC Number
  • 234-320-9
UNII
  • InChI=1S/7Mo.6H3N.24H2O/h;;;;;;;6*1H3;24*1H2 checkY
    Key: QGAVSDVURUSLQK-UHFFFAOYSA-N checkY
  • InChI=1/7Mo.6H3N.24H2O/h;;;;;;;6*1H3;24*1H2
    Key: QGAVSDVURUSLQK-UHFFFAOYAC
  • [Mo].[Mo].[Mo].[Mo].[Mo].[Mo].[Mo].O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.N.N.N.N.N.N
Properties
(NH4)6Mo7O24
Molar mass 1163.9 g/mol
1235.86 g/mol (tetrahydrate)
Appearance white to yellow-green crystalline solid
Density 2.498 g/cm3
Melting point ~90 ˚C (loses water molecule)
190 °C (decomp.)
43 g/100 ml (tetrahydrate)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Irritant
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
0
0
Flash point Non-flammable
Related compounds
Other anions
 Ammonium orthomolybdate
Ammonium dimolybdate
Other cations
 Potassium paramolybdate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Ammonium heptamolybdate is an odourless crystalline compound ranging in colour from white to yellow-green. It is usually encountered as the tetrahydrate, whose chemical formula is (NH4)6Mo7O24·4H2O. It is 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 species.

Synthesis

Ammonium heptamolybdate is easily prepared by dissolving molybdenum trioxide in an excess of aqueous ammonia and evaporating the solution at room temperature. While the solution evaporates, the excess of ammonia escapes. This method results in the formation of six-sided transparent prisms of the tetrahydrate of ammonium heptamolybdate.[1]

Solutions of ammonium paramolybdate react with acids to form molybdic acid and an ammonium salt. The pH value of a concentrated solution will lie between 5 and 6.

Uses

  • as an analytical reagent to measure the amount of phosphates, silicates, arsenates and lead in aqueous solution (e.g. pigments, river water, sea water etc.)[2]
  • in the production of molybdenum metal and ceramics
  • in the preparation of dehydrogenation and desulphurisation catalysts
  • in the fixing of metals
  • in electroplating
  • in fertilizers for crops.
  • as a negative stain in biological electron microscopy, typically in the 3–5% (vol/vol) concentration range and in the presence of trehalose[3]; or at saturated concentration to perform cryo-negative staining.[4][5]

Safety

Ammonium paramolybdate is harmful if swallowed or inhaled. It causes irritation to the eyes, skin, and respiratory tract. It affects kidneys and blood.

References

  1. ^ L. Svanberg & H. Struve, J. pr. Ch. 44 [1848], p. 282; cited in Gmelin's Handbuch für Anorganische Chemie, 53, p. 255.
  2. ^ Parsons, T.,Maita, V., & Lalli, C. (1984). A manual of chemical and biological methods for seawater analysis. Oxford: Pergamon.
  3. ^ Harris, J.R. and Horne, R.W. 1991. Negative staining, in Harris J. R. (Ed.), Electron Microscopy in Biology, Oxford University Press, Oxford.
  4. ^ Adrian, M., Dubochet, J., Fuller, S.D. and Harris, J.R. 1998. Cryo-negative Staining. Micron 29, p. 145–160; doi:10.1016/S0968-4328(97)00068-1.
  5. ^ De Carlo, S., El-Bez, C., Alvarez-Rúa, C., Borge, J. and Dubochet, J. 2002. Cryo-negative staining reduces electron-beam sensitivity of vitrified biological particles. J. Struct. Biol. 138, p. 216–226; doi:10.1016/S1047-8477(02)00035-7; PMID 12217660.

External links

source: https://en.wikipedia.org/w/index.php?diff=399510128&oldid=399508834

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