Nitratoauric acid
Names
IUPAC name
Hydrogen tetranitratoaurate(III)[1]
Other names
  • Gold(III) nitrate
  • Auronitric acid
  • Gold(III) hydrogen nitrate
  • Aurinitric acid
Identifiers
ChemSpider
EC Number
  • 236-687-0
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
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Oxidizing
GHS labelling:
GHS03: Oxidizing
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)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
1
0
2
OX
Related compounds
Other anions
 Chloroauric acid
Other cations
 Potassium tetranitratoaurate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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]

Preparation and reactions

Nitratoauric 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 + 3H2O

This compound reacts with potassium nitrate to form potassium tetranitratoaurate at 0 °C:[6]

HAu(NO3)4 + KNO3 → KAu(NO3)4 + HNO3

Properties

Nitratoauric 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

The 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]

References

  1. ^ a b c "Gold Nitrate". ESPI Metals.
  2. ^ 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.
  3. ^ A. Jamieson Walker (1924). The Alkali-metals and Their Congeners. the University of California: C. Griffin. p. 349.
  4. ^ D. P. Graddon; H. Taube; A. G. Maddock (2017). An Introduction to Co-Ordination Chemistry (Ebook) (2nd ed.). Elsevier Science. p. 148. ISBN 9781483184111.
  5. ^ a b Harry Mann Gordin (1913). Elementary Chemistry (1 ed.). the University of Wisconsin - Madison: Medico-dental Publishing Company. p. 437.
  6. ^ Ripan R., Chetyanu I. (1972). Inorganic chemistry. Chemistry of metals. Vol. 2. Moscow: World.
  7. ^ 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.
  8. ^ 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.
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