Étude polarographique du niobium dans les mélanges eau – fluorure d'hydrogène

1983 ◽  
Vol 61 (12) ◽  
pp. 2699-2702 ◽  
Author(s):  
H. Ménard ◽  
R. Beaudoin
Keyword(s):  
Hydrogen Fluoride ◽  
Hydrofluoric Acid ◽  
Water Hydrogen

Solubilization in hydrogen fluoride is required for the analysis of some minerals. A method of analysis directly applicable to water – hydrogen fluoride mixtures was worked out.However, in 50% hydrofluoric acid niobium is soluble as [Formula: see text] complex, which can be reduced with a polarographic electrode at a potential of −0.880 V vs. E.C.S. For concentrations lower than 45% in HF, the niobium complex is hydrated and exists as a non-reducible ion [Formula: see text].

ChemInform Abstract: REDOX PROPERTIES AND SOLVATION OF METALLIC IONS IN WATER HYDROGEN FLUORIDE MIXTURES

1979 ◽  
Vol 10 (43) ◽  
Author(s):  
J. DEVYNCK ◽  
A. VAILLANT ◽  
B. TREMILLON ◽  
F. LEBLOND-ROTHIER ◽  
H. MENARD
Keyword(s):  
Hydrogen Fluoride ◽  
Redox Properties ◽  
Metallic Ions ◽  
Water Hydrogen

scholarly journals Study of the content of fluorides in atmospheric air in Bokhtar region and Tursunzade city of Tajikistan

2021 ◽  
Vol 2 (1) ◽  
pp. 11-18
Author(s):  
Khuseyn Egamnazarov ◽  
Babaev Ikram Islamovich ◽  
Aliev Samardin Partoevich ◽  
Abdullozoda Said Murtazo
Keyword(s):  
Hydrogen Fluoride ◽  
Hydrofluoric Acid ◽  
Maximum Amount ◽  
Public Healthcare ◽  
Control Zone ◽  
Atmospheric Air ◽  
The Public ◽  
Fluorine Compounds ◽  
And Control ◽  
The City

Background: The emission and presence of air pollutants such as fluorides has over burdenized the public healthcare issues. The current study aimed to determine the content of fluorides in atmospheric air in Bokhtar region and Tursunzade city of Tajikistan. Methods: Based on the direction of wind, two zones were selected in the current study: experimental and control. In the first (experimental) zone, those areas were selected where the western, northern and northeastern directions of wind was significant. Dzhura Rakhmonov was assigned to the control zone with the shortest time for the eastward winds. In general, 72 samples of atmospheric air were taken in 12 settlements of the city of Tursunzade and 90 samples of atmospheric air in the Bokhtar region of the Khatlon province. To determine fluorine in air, a potentiometric method with an ion-selective electrode was used, which makes it possible to measure the potential concentrations of fluorides in atmospheric air. Results: Compounds of gaseous (hydrogen fluoride) and solid fluorine (salts of hydrofluoric acid), which are the main emission from various sources, were found in the atmospheric air of the populated areas of the city of Tursunzade, where the aluminum plant industry is located. The maximum amount of hydrogen fluoride in the experimental zone (Jamoat and Navobod) with a western wind direction was found in the autumn, which exceeded the MPC. However, the amount of solid fluorides in the western direction of the wind ranged from 0.01 to 1.0 mg / m3, which did not exceed the MPC value and was not significant. In control zone (Dzhura Rakhmonov) the said pollutants hydrogen fluoride and solid fluorine were not significant in autumn within accordance to MPC limit. The results of the study of atmospheric air in 15 administrative cities and districts of the Bokhtar region showed a complete absence of solid fluorides in all samples of atmospheric air. Conclusion: Compounds of gaseous fluorine and salts of hydrofluoric acid were found in the atmospheric air of populated areas of the city of Tursunzade, and no significant amounts in the Bokhtar region according to MPC and control. The maximum amount of fluorine compounds was found in the experimental zone (Jamoat Navobod) of the city of Tursunzade.

scholarly journals Experiments on the Release of CMOS-Micromachined Metal Layers

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Daniel Fernández ◽  
Jordi Ricart ◽  
Jordi Madrenas
Keyword(s):  
Acetic Acid ◽  
Silicon Dioxide ◽  
Hydrogen Fluoride ◽  
Hydrofluoric Acid ◽  
Ammonium Fluoride ◽  
Cmos Technology ◽  
Multilayer Structures ◽  
Structural Elements ◽  
Mems Devices ◽  
Metal Layers

We present experimental results on the release of MEMS devices manufactured using the standard CMOS interconnection metal layers as structural elements and the insulating silicon dioxide as sacrificial layers. Experiments compare the release results of four different etching agents in a CMOS technology (hydrofluoric acid, ammonium fluoride, a mixture of acetic acid and ammonium fluoride, and hydrogen fluoride), describe various phenomena found during the etching process, and show the release results of multilayer structures.

Sign in / Sign up

Export Citation Format

Share Document