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{{chembox {{chembox
| Verifiedfields = changed
⚫ | verifiedrevid = 399508834
| Watchedfields = changed
⚫ | verifiedrevid = 445368591
| Name =
| ImageFile = Heptamolybdenan amonný.JPG | ImageFile = Heptamolybdenan amonný.JPG
| ImageSize = | ImageSize =
| ImageFile1 = | ImageFile1 =
| IUPACName = Ammonium docosaoxoheptamolybdate(6–) | IUPACName = Ammonium docosaoxoheptamolybdate(6–)
| OtherNames = Ammonium molybdate<br />Ammonium paramolybdate<br /> (''see text'') | OtherNames = Ammonium molybdate<br />Ammonium paramolybdate<br /> (''see text'')
| SystematicName =
| Section1 = {{Chembox Identifiers | Section1 = {{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 23786 | ChemSpiderID = 23786
| UNII_Ref = {{fdacite|correct|FDA}} | UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 21Y68J178E | UNII = 21Y68J178E
| UNII1_Ref = {{fdacite|correct|FDA}}
| UNII1 = OGI154X474
| UNII1_Comment = (tetrahydrate)
| InChI = 1/7Mo.6H3N.24H2O/h;;;;;;;6*1H3;24*1H2 | InChI = 1/7Mo.6H3N.24H2O/h;;;;;;;6*1H3;24*1H2
| InChIKey = QGAVSDVURUSLQK-UHFFFAOYAC | InChIKey = QGAVSDVURUSLQK-UHFFFAOYAC
| SMILES = .......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 = ......(=O)(=O).(=O)(=O).(=O)(=O)
| SMILES1 = ...3479%12125()()O1%10()()O%11()()(O8()()(O6()()(O()()(O2)(O3)456)78)9%10%11)O%12...
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} | 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_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = QGAVSDVURUSLQK-UHFFFAOYSA-N | StdInChIKey = QGAVSDVURUSLQK-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 12027-67-7 | CASNo = 12027-67-7
| CASNo_Ref = {{cascite|correct|CAS}} | CASNo2_Ref = {{cascite|correct|CAS}}
| CASOther = <br/>12054-85-2 (tetrahydrate) | CASNo2 = 12054-85-2
| CASNo2_Comment = (tetrahydrate)
| PubChem =
| EINECS = 234-320-9 | PubChem = 71306766
| EINECS = 234-320-9
}} }}
| Section2 = {{Chembox Properties | Section2 = {{Chembox Properties
| Formula = (NH<sub>4</sub>)<sub>6</sub>Mo<sub>7</sub>O<sub>24</sub> | Formula = (NH<sub>4</sub>)<sub>6</sub>Mo<sub>7</sub>O<sub>24</sub>
| MolarMass = 1163.9 g/mol<br>1235.86 g/mol (tetrahydrate) | MolarMass = 1163.9 g/mol<br>1235.86 g/mol (tetrahydrate)
| Appearance = white to yellow-green crystalline solid | Appearance = white solid
| Density = 2.498 g/cm<sup>3</sup> | Density = 2.498 g/cm<sup>3</sup>
| MeltingPt = ~90 ˚C (loses water molecule) <br>190 °C (decomp.) | MeltingPt = ~90 ˚C (loses water molecule) <br>190 °C (decomp.)
| BoilingPt = | BoilingPt =
| Solubility = 43 g/100 ml (tetrahydrate) | Solubility = 65.3 g / 100 ml (tetrahydrate)
}} }}
| Section3 =
| Section4 =
| Section5 =
| Section6 =
| Section7 = {{Chembox Hazards | Section7 = {{Chembox Hazards
| ExternalSDS =
| ExternalMSDS=
⚫ | MainHazards = Irritant
| EUIndex = Not listed
⚫ | NFPA-H = 2
⚫ | MainHazards = Irritant
| RPhrases = | NFPA-F = 0
| SPhrases = | NFPA-R = 0
| NFPA-H = 2 | NFPA-S =
⚫ | FlashPt = Non-flammable
⚫ | NFPA-F = 0
| NFPA-R = 0
| NFPA-O =
⚫ | FlashPt = Non-flammable
}} }}
| Section8 = {{Chembox Related | Section8 = {{Chembox Related
| OtherAnions = ]<br />Ammonium dimolybdate | OtherAnions = ]<br />Ammonium dimolybdate
| OtherCations = Potassium paramolybdate | OtherCations = Potassium paramolybdate
| OtherCpds = ]<br/>] | OtherCompounds = ]<br/>]
}} }}
}} }}
'''Ammonium heptamolybdate''' is an odourless crystalline compound ranging in colour from white to yellow-green. It is usually encountered as the tetrahydrate, whose ] is (NH<sub>4</sub>)<sub>6</sub>Mo<sub>7</sub>O<sub>24</sub>·4H<sub>2</sub>O. It is often referred to as '''ammonium paramolybdate''' or simply as '''ammonium molybdate''', although ammonium molybdate can also refer to ], (NH<sub>4</sub>)<sub>2</sub>MoO<sub>4</sub>, and several other species. '''Ammonium heptamolybdate''' is the ] whose ] is (NH<sub>4</sub>)<sub>6</sub>Mo<sub>7</sub>O<sub>24</sub>, 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 ], (NH<sub>4</sub>)<sub>2</sub>MoO<sub>4</sub>, and several other compounds. It is one of the more common molybdenum compounds.<ref name=Ull/>


== Synthesis == == 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.<ref>L. Svanberg & H. Struve, J. pr. Ch. '''44''' , p.&nbsp;282; cited in Gmelin's Handbuch für Anorganische Chemie, ''53'', p.&nbsp;255.</ref> 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.<ref>L. Svanberg & H. Struve, ''J. pr. Ch.'' '''44''' , p.&nbsp;282; cited in ''Gmelin's Handbuch für Anorganische Chemie'', ''53'', p.&nbsp;255.</ref>


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

==Structure==
The compound was first analyzed crystallographically by Lindqvist, but has been reanalyzed.<ref name=Evans>Evans, H.T., Jr.; Gatehouse, B. M.; Leverett, P. "Crystal Structure of the Heptamolybdate(VI) (paramolybdate) ion, (Mo<sub>7</sub>O<sub>24</sub>)<sup>6−</sup>, in the ammonium and potassium tetrahydrate salts" Journal of the Chemical Society. Dalton Transactions, Inorganic Chemistry1975, p.505-p514.</ref> All Mo centers are octahedral. Some oxide ligands are terminal, some doubly bridging, and a few are triply ]s.
]


== Uses == == Uses ==
*as an analytical ] to measure the amount of ]s, ], ]s and ] in ] (e.g. pigments, river water, sea water etc.)<ref>Parsons, T.,Maita, V., & Lalli, C. (1984). A manual of chemical and biological methods for seawater analysis. Oxford: Pergamon.</ref> *as an analytical ] to measure the amount of ]s, ], ]s and ] in ] (e.g. pigments, river water, sea water etc.)<ref>Parsons, T.; Maita, V. & Lalli, C. (1984). ''A manual of chemical and biological methods for seawater analysis''. Oxford: Pergamon.</ref>
*in the production of ] metal and ]s *in the production of ] metal and ]s
*in the preparation of dehydrogenation and desulphurisation ] *in the preparation of dehydrogenation and ] ]s
*in the fixing of metals *in the fixing of metals
*in ] *in ]
*in fertilizers for crops. *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<ref>Harris, J.R. and Horne, R.W. 1991. Negative staining, in Harris J. R. (Ed.), Electron Microscopy in Biology, Oxford University Press, Oxford.</ref>; or at saturated concentration to perform cryo-negative staining.<ref>Adrian, M., Dubochet, J., Fuller, S.D. and Harris, J.R. 1998. Cryo-negative Staining. Micron 29, p.&nbsp;145–160; {{DOI|10.1016/S0968-4328(97)00068-1}}.</ref><ref>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.&nbsp;216–226; {{DOI|10.1016/S1047-8477(02)00035-7}}; PMID 12217660.</ref> *as a negative stain in biological electron microscopy, typically in the 3–5% (vol/vol) concentration range and in the presence of trehalose;<ref>Harris, J. R. and Horne, R. W. 1991. "Negative staining", in Harris J. R. (Ed.), ''Electron Microscopy in Biology'', Oxford University Press, Oxford.</ref> or at saturated concentration to perform cryo-negative staining.<ref>{{cite journal | doi = 10.1016/S0968-4328(97)00068-1| pmid = 9684350| title = Cryo-negative staining| journal = Micron| volume = 29| issue = 2–3| pages = 145–160| year = 1998| last1 = Adrian| first1 = Marc| last2 = Dubochet| first2 = Jacques| last3 = Fuller| first3 = Stephen D.| last4 = Harris| first4 = J. Robin}}</ref><ref>{{cite journal | doi = 10.1016/S1047-8477(02)00035-7 | pmid = 12217660 | title = Cryo-negative staining reduces electron-beam sensitivity of vitrified biological particles | journal = Journal of Structural Biology | volume = 138 | issue = 3 | pages = 216–226 | year = 2002 | last1 = De Carlo | first1 = S. | last2 = El-Bez | first2 = C. | last3 = Alvarez-Rúa | first3 = C. | last4 = Borge | first4 = J. | last5 = Dubochet | first5 = J. }}</ref>
*For the detection of recreational drugs as a component of the ]

==Related compounds==
Potassium heptamolybdate, also obtained as the tetrahydrate, is very similar to the ammonium salt.<ref name=Evans/>


== Safety == == Safety ==
Molybdates are typically of low toxicity, so much so that few reports of incidents have ever been reported.<ref name=Ull>{{Ullmann|doi = 10.1002/14356007|year = 2000|title=Molybdenum and Molybdenum Compounds|display-authors=etal|first1=Roger F.|last1=Sebenik}}</ref>
Ammonium paramolybdate is harmful if swallowed or inhaled. It causes irritation to the eyes, skin, and respiratory tract. It affects kidneys and blood.


== References == == References ==
{{reflist}} {{reflist}}


== External links == == See also ==
] aka ] links to here.
*

{{Ammonium salts}}


] ]
] ]

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Latest revision as of 22:19, 11 December 2021

Ammonium heptamolybdate
Names
IUPAC name Ammonium docosaoxoheptamolybdate(6–)
Other names Ammonium molybdate
Ammonium paramolybdate
(see text)
Identifiers
CAS Number
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.553 Edit this at Wikidata
EC Number
  • 234-320-9
PubChem CID
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/7Mo.6H3N.24H2O/h;;;;;;;6*1H3;24*1H2Key: QGAVSDVURUSLQK-UHFFFAOYSA-N
  • InChI=1/7Mo.6H3N.24H2O/h;;;;;;;6*1H3;24*1H2Key: QGAVSDVURUSLQK-UHFFFAOYAC
SMILES
  • ......(=O)(=O).(=O)(=O).(=O)(=O)
  • ...3479%12125()()O1%10()()O%11()()(O8()()(O6()()(O()()(O2)(O3)456)78)9%10%11)O%12...
Properties
Chemical formula (NH4)6Mo7O24
Molar mass 1163.9 g/mol
1235.86 g/mol (tetrahydrate)
Appearance white solid
Density 2.498 g/cm
Melting point ~90 ˚C (loses water molecule)
190 °C (decomp.)
Solubility in water 65.3 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
Safety data sheet (SDS) External MSDS
Related compounds
Other anions Ammonium orthomolybdate
Ammonium dimolybdate
Other cations Potassium paramolybdate
Related compounds Molybdenum(VI) oxide
Molybdic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). ☒N verify (what is  ?) Infobox references
Chemical compound

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.

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.

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.

Structure

The compound was first analyzed crystallographically by Lindqvist, but has been reanalyzed. All Mo centers are octahedral. Some oxide ligands are terminal, some doubly bridging, and a few are triply bridging ligands.

The salt contains the heptamolybdate hexaanion.

Uses

Related compounds

Potassium heptamolybdate, also obtained as the tetrahydrate, is very similar to the ammonium salt.

Safety

Molybdates are typically of low toxicity, so much so that few reports of incidents have ever been reported.

References

  1. ^ Sebenik, Roger F.; et al. (2000). "Molybdenum and Molybdenum Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007. ISBN 978-3527306732.
  2. L. Svanberg & H. Struve, J. pr. Ch. 44 , p. 282; cited in Gmelin's Handbuch für Anorganische Chemie, 53, p. 255.
  3. ^ Evans, H.T., Jr.; Gatehouse, B. M.; Leverett, P. "Crystal Structure of the Heptamolybdate(VI) (paramolybdate) ion, (Mo7O24), in the ammonium and potassium tetrahydrate salts" Journal of the Chemical Society. Dalton Transactions, Inorganic Chemistry1975, p.505-p514.
  4. Parsons, T.; Maita, V. & Lalli, C. (1984). A manual of chemical and biological methods for seawater analysis. Oxford: Pergamon.
  5. Harris, J. R. and Horne, R. W. 1991. "Negative staining", in Harris J. R. (Ed.), Electron Microscopy in Biology, Oxford University Press, Oxford.
  6. Adrian, Marc; Dubochet, Jacques; Fuller, Stephen D.; Harris, J. Robin (1998). "Cryo-negative staining". Micron. 29 (2–3): 145–160. doi:10.1016/S0968-4328(97)00068-1. PMID 9684350.
  7. De Carlo, S.; El-Bez, C.; Alvarez-Rúa, C.; Borge, J.; Dubochet, J. (2002). "Cryo-negative staining reduces electron-beam sensitivity of vitrified biological particles". Journal of Structural Biology. 138 (3): 216–226. doi:10.1016/S1047-8477(02)00035-7. PMID 12217660.

See also

Phosphate test aka Deniges' method links to here.

Ammonium salts
Inorganic salts
monatomic anions
oxyanions
other anions
Organic salts
Categories: