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Ammonium fluoride is a critical component of buffered oxide etch (BOE), a wet etchant used in microfabrication. It acts as the buffering agent in a solution of concentrated HF , creating an etchant with a more controllable rate of etching (than that of simple concentrated HF solutions).
Chemical formula Synonyms CAS number NBr 3: nitrogen tribromide: 15162–90–0 NCl 3: nitrogen trichloride: 10025–85–1 NF 3: nitrogen trifluoride: 7783–54–2 NH 3: ammonia: 7664–41–7 NH 4 Cl: ammonium chloride: 12125–02–9 NH 4 HCO 3: ammonium bicarbonate: 1066–33–7 NH 4 NO 3: ammonium nitrate: 6484–52–2 NH 4 OH: ammonium ...
Ammonium bifluoride, as its name indicates, contains an ammonium cation ([NH 4] +), and a bifluoride (or hydrogen difluoride) anion ([HF 2] −).The triatomic bifluoride anion features a strong three-center four-electron bond (specifically, a symmetrical hydrogen bond) with a bond energy greater than 155 kJ/mol, [2] and an H-F length of 114 pm. [3]
Ammonium fluorosilicate (also known as ammonium hexafluorosilicate, ammonium fluosilicate or ammonium silicofluoride) has the formula (NH 4) 2 SiF 6. It is a toxic chemical, like all salts of fluorosilicic acid. [4] It is made of white crystals, [5] which have at least three polymorphs [6] and appears in nature as rare minerals cryptohalite or ...
Most other soluble salts of fluoride are in fact bifluorides, HF 2 –. Historically, there have been two main approaches to prepare tetramethylammonium fluoride: hydrofluoric acid neutralization of tetramethylammonium hydroxide, and salt metathesis between different ammonium salts and inorganic fluoride sources, such as KF or CsF. [1]
Benzyltrimethylammonium fluoride is a quaternary ammonium salt. It is commercially available as the hydrate. The compound is a source of organic-soluble fluoride to removal of silyl ether protecting groups. As is the case for tetra-n-butylammonium fluoride and most other quaternary ammonium fluorides, the compound cannot be obtained in ...
Dried tetra-n-butylammonium fluoride was the preferred fluoride source in one study, [6] but CsF has been used in difficult cases with excellent results. [ 7 ] Aryl nonaflates can be prepared straightforwardly from phenols and NfF in the presence of bases such as potassium carbonate [ 8 ] and Et 3 N [ 4 ] in near quantitative yields.
The bifluoride ion has a linear, centrosymmetric structure (D ∞h symmetry), with an F−H bond length of 114 pm. [1] The bond strength is estimated to be greater than 155 kJ/mol. [2] In molecular orbital theory, the atoms are modeled to be held together by a 3-center 4-electron bond (symmetrical hydrogen bond), [3] in a sort of hybrid between a hydrogen bond and a covalent bond.