Nitratoauric acid, hydrogen tetranitratoaurate, or simply called gold(III) nitrate is a crystalline gold compound that forms the trihydrate, HAu(NO3)4·3H2O or more correctly H5O2Au(NO3)4·H2O.[3][2] This compound is an intermediate in the process of extracting gold.[4] In older literature it is also known as aurinitric acid.[5]
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| Names | |
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| IUPAC name
Hydrogen tetranitratoaurate(III)[1]
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Other names
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| Identifiers | |
| ChemSpider | |
| EC Number |
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PubChem CID
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| Properties | |
| HAu(NO3)4 | |
| Molar mass | 445.99 g/mol (anhydrous) 500.04 g/mol (trihydrate) |
| Appearance | Brown Crystals[1] |
| Density | 2.84 g/cm3[1] |
| Melting point | 72.6 °C (162.7 °F; 345.8 K)[2] |
| Hydrolyzes[2] | |
| Solubility in nitric acid | Insoluble (0 °C) Soluble (30 °C) |
| Structure[2] | |
| Monoclinic | |
| C2/c | |
a = 1214.5 pm, b = 854.4 pm, c = 1225.7 pm
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| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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Oxidizing |
| GHS labelling: | |
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| Danger | |
| H272, H302, H312, H315, H318, H332, H335 | |
| P210, P220, P221, P261, P280, P302+P352, P304+P340, P305+P351+P338, P332+P313 | |
| NFPA 704 (fire diamond) | |
| Related compounds | |
Other anions
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Chloroauric acid |
Other cations
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Potassium tetranitratoaurate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation and reactions
editNitratoauric acid is prepared by the reaction of gold(III) hydroxide and concentrated nitric acid at 100 °C:[2][5]
- Au(OH)3 + 4HNO3 → HAu(NO3)4 + 3 H2O
This compound reacts with potassium nitrate to form potassium tetranitratoaurate at 0 °C:[6]
- HAu(NO3)4 + KNO3 → KAu(NO3)4 + HNO3
Properties
editNitratoauric acid trihydrate decomposes to the monohydrate at 72 °C. If continually heated to 203 °C, it decomposes to auric oxide.[2]
Simple gold(III) nitrate
editThe production of the simple nitrate (Au(NO3)3) was reported from the reaction of gold oxide and dinitrogen pentoxide, however, this was later proven to be nitronium tetranitratoaurate ((NO2)Au(NO3)4).[7][8]
However, the ammine complex of the simple gold nitrate is known. Au(NH3)4(NO3)3, also known as tetraaminegold(III) nitrate, is produced by the addition of ammonium nitrate to a solution of chloroauric acid. The hydrolysis of this compound produces fulminating gold.[9][10][11]
References
edit- ^ a b c "Gold Nitrate". ESPI Metals.
- ^ a b c d e f Oliver Büchner; Mathias S. Wickleder (2004). "Tetranitratogoldsäure, (H5O2)[Au(NO3)4]·H2O: Synthese, Kristallstruktur und thermisches Verhalten des ersten sauren Nitrates des Goldes". Zeitschrift für anorganische und allgemeine Chemie (in German). 630 (7): 1079–1083. doi:10.1002/zaac.200400092.
- ^ A. Jamieson Walker (1924). The Alkali-metals and Their Congeners. the University of California: C. Griffin. p. 349.
- ^ D. P. Graddon; H. Taube; A. G. Maddock (2017). An Introduction to Co-Ordination Chemistry (Ebook) (2nd ed.). Elsevier Science. p. 148. ISBN 9781483184111.
- ^ a b Harry Mann Gordin (1913). Elementary Chemistry (1 ed.). the University of Wisconsin - Madison: Medico-dental Publishing Company. p. 437.
- ^ Ripan R., Chetyanu I. (1972). Inorganic chemistry. Chemistry of metals. Vol. 2. Moscow: World.
- ^ B. O. Field; C. J. Hardy (1964). "Volatile and anhydrous nitrato-complexes of metals: preparation by the use of dinitrogen pentoxide, and measurement of infrared spectra". Journal of the Chemical Society: 4428–4434. doi:10.1039/JR9640004428.
- ^ Mathias S. Wickleder; Oliver Büchner; Frauke Gerlach; Mandus Necke; Katharina Al-Shamery; Thomas Wich; Tim Luttermann (2008). "Synthesis, Characterization and Electron Beam Assisted Decomposition of (NO2)[Au(NO3)4]". Chemistry of Materials. 20 (16): 5181–5185. doi:10.1021/cm800066r.
- ^ Weishaupt, Martin; Strähle, Joachim (1976). "Kristallstruktur und Schwingungsspektrum des Tetrammingold(III) -nitrats" [Crystal Structure and Vibrational Spectrum of Tetraamminegold(III)-Nitrate]. Zeitschrift für Naturforschung B (in German). 31 (5): 554–557. doi:10.1515/znb-1976-0505.
- ^ Skibsted, L. H.; Bjerrum, Jannik (1974). "Studies on Gold Complexes. I. Robustness, Stability and Acid Dissociation of the Tetramminegold(III) Ion". Acta Chemica Scandinavica. 28: 740–746. doi:10.3891/acta.chem.scand.28a-0740.
- ^ Michel Manfait; Alain J.P. Alix; Charles Kappenstein (1981). "Raman and infrared studies of the square planar tetraammine gold(III) nitrate and its deuterate". Inorganica Chimica Acta. 50: 147–152. doi:10.1016/S0020-1693(00)83735-4.