The Vapor Pressure of Germanium Dioxide

Abstract

The apparent vapor pressure of solid germanium dioxide, or the dissociation pressure for the reaction GeO2(c) = GeO(g)+1/2 O2(g), was measured over the temperature range 1,040 – 1,100°C by the Knudsen’s effusion method; the results are expressed by equation (4). From the free energy equation, the heat of reaction, the free energy and the entropy change of the reaction were calculated as ΔH298=121.7±0.3kcal./mol., ΔG298=101.7kcal./mol. and ΔS298=67.3 e.u., respectively. The heat of reaction is in good agreement with the value calculated from accessible thermal data. The normal entropy of solid germanium dioxide was calculated as S298=10.8±1.0 e.u., which is in agreement with the computed value obtained by Bues and von Wartenberg.

Detached crystal growth from melt by the axial heat processing technique

“…Moreover, an off-white scale deposited inside the crucibles after some growth experiments is proved to be a GeO 2 scale by our Xray analysis (Fig. 3) and the literature survey [20][21][22][23][24][25][26][27][28]. The scale is more visible in case of longer growth times, indicating formation of a thicker oxide scale in time.…”

“…Oxidation studies have shown that Ge forms GeO at low temperatures and GeO 2 at higher temperatures and at higher oxygen partial pressures [20][21][22][23][24][25][26][27][28]. It has been also reported that GeO decomposes at around 700 1C [29].…”

GeO2 Thin Film Deposition on Graphene Oxide by the Hydrogen Peroxide Route: Evaluation for Lithium-Ion Battery Anode

“…In addition, hydrothermal and solvothermal processes that can be easily accomplished under laboratory conditions require glass- or Teflon-lined pressure tanks due to germanium salt (e.g., GeCl 4 ) acidity and corrosivity under elevated temperatures. Moreover, since buffer addition is impossible, the hydrothermal process should be carried out with dilute solutions, which further increases the volume of the lined pressure reactors and their cost . Note that heat treatment of the dry active material is relatively inexpensive since a pressure reactor is not needed and the volumes involved are small compared to hydrothermal processing.…”

Thermochemical study of gaseous salts of oxygen-containing acids: XX. Germanium salts

“…Gas phase above GeO, GeO 2 , and GeO 2 -Ge mixtures was repeatedly studied [3][4][5][6]. Germanium dioxide passes in vapor in the temperature range 1300-1500 K according to Eq.…”

“…The ion GeBO 2 + is a product of dissociative ionization of the GeB 2 O 4 molecule [Eq. (4)]. If the ion GeBO 2 + were a product of the molecule GeBO 2 direct ionization, its appearance energy would be considerably lower than that of GeB 2 O 4 [22].…”