TY - JOUR
T1 - Structure of a gold(III) hydroxide and determination of its solubility
AU - Kawamoto, Daisuke
AU - Ando, Hiroaki
AU - Ohashi, Hironori
AU - Kobayashi, Yasuhiro
AU - Honma, Tetsuo
AU - Ishida, Tamao
AU - Tokunaga, Makoto
AU - Okaue, Yoshihiro
AU - Utsunomiya, Satoshi
AU - Yokoyama, Takushi
N1 - Publisher Copyright:
© 2016 The Chemical Society of Japan.
PY - 2016
Y1 - 2016
N2 - A representative gold(III) complex ion ([AuCl4]), successively hydrolyzes to form [AuCl4n(OH)n] (n = 04) in aqueous solution as the pH increases and, finally, precipitates. It has been referred to as gold(III) hydroxide for the past fifty years. However, whether the precipitate is gold(III) hydroxide (Au(OH)3) or hydrous gold(III) oxide (Au2O3nH2O) has remained uncertain. Few studies have been conducted to determine its chemical and physical properties. The aim of this investigation is to identify the precipitate and to determine its solubility. The precipitate was X-ray amorphous. Based on the transmission electron microscopy (TEM) observation, the shape was spherical and the particle diameter was approximately 9 nm. From the results of 197Au Mössbauer spectroscopy, Au L3-edge X-ray absorption (XA) spectroscopy and thermogravimetry/ differential thermal analysis (TG/DTA) measurements, the precipitate composition was estimated to be Au(OH)3. Based on the composition, its structure was proposed to be a linear polymer. Moreover, its solubility at 298K was determined to be 0.00120 g/100 g of H2O. This chemical and physical properties information of Au(OH)3 is essential for gold chemistry, for example, for preparing supported gold catalyst.
AB - A representative gold(III) complex ion ([AuCl4]), successively hydrolyzes to form [AuCl4n(OH)n] (n = 04) in aqueous solution as the pH increases and, finally, precipitates. It has been referred to as gold(III) hydroxide for the past fifty years. However, whether the precipitate is gold(III) hydroxide (Au(OH)3) or hydrous gold(III) oxide (Au2O3nH2O) has remained uncertain. Few studies have been conducted to determine its chemical and physical properties. The aim of this investigation is to identify the precipitate and to determine its solubility. The precipitate was X-ray amorphous. Based on the transmission electron microscopy (TEM) observation, the shape was spherical and the particle diameter was approximately 9 nm. From the results of 197Au Mössbauer spectroscopy, Au L3-edge X-ray absorption (XA) spectroscopy and thermogravimetry/ differential thermal analysis (TG/DTA) measurements, the precipitate composition was estimated to be Au(OH)3. Based on the composition, its structure was proposed to be a linear polymer. Moreover, its solubility at 298K was determined to be 0.00120 g/100 g of H2O. This chemical and physical properties information of Au(OH)3 is essential for gold chemistry, for example, for preparing supported gold catalyst.
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U2 - 10.1246/bcsj.20160228
DO - 10.1246/bcsj.20160228
M3 - Article
AN - SCOPUS:85025834334
SN - 0009-2673
VL - 89
SP - 1385
EP - 1390
JO - Bulletin of the Chemical Society of Japan
JF - Bulletin of the Chemical Society of Japan
IS - 11
ER -