The complexing characteristics of insoluble selenides. 1. Silver selenide

Abstract

The aqueous solubility of the system silver selenide has been investigated in an inert atmosphere of nitrogen at a unit molar ionic strength and constant temperature of 25° C. The experimental evidence indicates the formation of two aqueous species [Ag2(HSe)(OH)], and [Ag(Se)2(OH)]4− in contact with the precipitated selenide in different regions of acidity. The former exists in acidic medium and has a pβ value of 48.49 ± 0.10 while the latter is stable only in alkaline conditions and has a pβ value of 24.07 ± 0.19. A mathematical treatment has been elaborated to identify and calculate the stability constants of such selenide complexes formed through a heterogeneous equilibrium.

The Thermodynamics of Selenium Minerals in Near-Surface Environments

“…These data are mostly calculated from calorimetric measurements (e.g., [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]) or experimental determinations of solubility (e.g., [35][36][37][38][39][40][41][42][43][44]). Such works are very numerous; their results are not always consistent with each other.…”

Silver Selenide Nanowires by Electrodeposition

“…The second reduction wave at Ϫ0.44 V is due to the reduction of selenous acid to selenium. 25 The third, a broad reduction wave beginning at about Ϫ0.50 V and z E-mail: guogl@pku.edu.cn centering at about Ϫ0.65 V is attributed to the induced deposition of Ag 2 Se due to the formation of insoluble Ag 2 Se (log K sp ϭ Ϫ63.7 26 ͒ according to Eq. 1…”

Effect of selenium on silver transport and precipitation by hydrothermal solutions: Thermodynamic description of the Ag-Se-S-Cl-O-H system

“…The vertical bar is an uncertainty of the ion association model (Akinfiev, 1995). Mehra and Gubeli (1970) did not eliminate the occurrence of colloidal species (Ag 2 Se) in the analyzed solution because of an insufficiently reliable filtration technique (Rai et al, 1995). Therefore, further it will be assumed that the solubility ΣAg = 10 -7.89 mol·kg -1 reported by Mehra and Gubeli (1970) (Fig.…”

“…Table 1. AKINFIEV, TAGIROV To describe the thermodynamic properties of Ag hydroselenide complexes, we had to apply simplified techniques on the basis of isocoulombic reactions. Only one experimental paper on the solubility of crystalline (Ag 2 Se) in aqueous solutions of selenides under standard conditions (Mehra and Gubeli, 1970) is available in the literature. The results of this experiment are shown in Fig.…”