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SiO 2 + 6 HF → H 2 SiF 6 + 2 H 2 O. A 5% to 9% hydrofluoric acid gel is also commonly used to etch all ceramic dental restorations to improve bonding. [6] For similar reasons, dilute hydrofluoric acid is a component of household rust stain remover, in car washes in "wheel cleaner" compounds, in ceramic and fabric rust inhibitors, and in water ...
SiO 2 + 4HF + 2NH 4 F → (NH 4) 2 SiF 6 + 2H 2 O. Concentrated HF (typically 49% HF in water) etches silicon dioxide too quickly for good process control and also peels photoresist used in photolithographic patterning. Buffered oxide etch is commonly used for more controllable etching. [1] Buffering HF with NH 4 F results in a solution with a ...
Hydrogen fluoride is typically produced by the reaction between sulfuric acid and pure grades of the mineral fluorite: [14] CaF 2 + H 2 SO 4 → 2 HF + CaSO 4. About 20% of manufactured HF is a byproduct of fertilizer production, which generates hexafluorosilicic acid. This acid can be degraded to release HF thermally and by hydrolysis: H 2 SiF ...
The optional second step (for bare silicon wafers) is a short immersion in a 1:100 or 1:50 solution of aqueous HF (hydrofluoric acid) at 25 °C for about fifteen seconds, in order to remove the thin oxide layer and some fraction of ionic contaminants. If this step is performed without ultra high purity materials and ultra clean containers, it ...
Lutetium(III) fluoride can be produced by reacting lutetium oxide with hydrogen fluoride, or reacting lutetium chloride and hydrofluoric acid. [8] It can also be produced by reacting lutetium sulfide and hydrofluoric acid: [9] 3 Lu 2 S 3 + 20 HF + (2 + 2x) H 2 O → 2 (H 3 O)Lu 3 F 10 ·xH 2 O↓ + 9 H 2 S↑ (x = 0.9) (H 3 O)Lu 3 F 10 → 3 ...
Elemental fluorine and virtually all fluorine compounds are produced from hydrogen fluoride or its aqueous solution, hydrofluoric acid. Hydrogen fluoride is produced in kilns by the endothermic reaction of fluorite (CaF 2) with sulfuric acid: [169] CaF 2 + H 2 SO 4 → 2 HF(g) + CaSO 4. The gaseous HF can then be absorbed in water or liquefied ...
Silicon wafers are treated with solutions of electronic-grade hydrofluoric acid in water, buffered water, or alcohol. One of the relevant reactions is simply removal of silicon oxides: SiO 2 + 4 HF → SiF 4 + 2 H 2 O. The key reaction however is the formation of the hydrosilane functional group.
Potassium fluoroborate is obtained by treating potassium carbonate with boric acid and hydrofluoric acid. B(OH) 3 + 4 HF → HBF 4 + 3 H 2 O 2 HBF 4 + K 2 CO 3 → 2 KBF 4 + H 2 CO 3. Fluoroborates of alkali metals and ammonium ions crystallize as water-soluble hydrates with the exception of potassium, rubidium, and cesium.