Potassium fluoride – Wikipedia

Potassium fluoride
Crystalline structure of potassium fluoride. __ K + __ F –
Identification
UICPA name	potassium fluoride
N O CAS	7789-23-3 (anhydrous) 13455-21-1 (dihydrate)
N O Echa	100,029.228
N O THIS	232-151-5
N O RTECS	TT0700000
Pubchem	522689
SMILES
Inches	Inches: 3D view Inchi=1/fh.k/h1H;/Q;+1/P-1 InChIKey : NOCBHXJPEDAR-UHFFFAOYSA-M
Appearance	Powder or crystals, white sometimes greenish, underdoors [ first ]
Chemicals
Formula	FK   [Isomers] KF
Molar mass [ 3 ]	58.096 7 ± 0,000 1 g/mol F 32,7 %, K 67,3 %,
Dipolar moment	8,585 ± 0.003 D [ 2 ]
Physical properties
T° fusion	858 °C [ first ]
T° boiling	1 502 °C [ first ]
Solubility	485 g · l -first (water, 20 °C ) [ first ]
Volumic mass	2.48 g · cm -3 [ first ]
Crystallography
Structure type	NaCl [ 4 ]
Precautions
SGH [ 5 ]
Danger after-content-x4 H301 , H311 And H331 H301 : Toxic in case of ingestion H311 : Toxic by skin contact H331 : Toxic by inhalation
Simdut [ 6 ]
D1B, D2a, D1B : Toxic material with severe immediate effects Transport of dangerous goods: class 6.1 Group III D2a : Very toxic material with other toxic effects Chronic toxicity: fluorosis Disclosure at 1.0% according to the ingredient disclosure list
Transport [ first ]
Code Kemler : 60 : toxic material or with a minor degree of toxicity UN number: 1812 : Potassium fluoride Class: 6.1 Label : 6.1 : Toxic materials
Ecotoxicology
DL 50	245 mg kg −1 (rat, oral) [ 7 ]
IS units and CNTP , unless otherwise stated.
modifier

The potassium fluoride is an inorganic compound of Formula KF. After hydrogen fluoride, it is the main source of fluoride ion used in industry and chemistry. It is an alkaline metal halogenure (in) Naturally present in the form of a rare mineral, carobbiitis. KF solutions can attack glass due to the formation of soluble fluorosilicates, even if fluorhydrical acid is more effective for this task.

Potassium fluoride is in the form of a hygroscopic white powder, generally in its dihydrate form. Dihydrate melts to forty six °C in its crystallization water. We can dissolve 485 g potassium fluoride in a liter of water to 20 °C .

Potassium fluoride has a standard ΔH formation enthalpy _f ° = -569 kj / times ^{[ 8 ]}

Because natural potassium contains 0.0118% of the radiisotope ⁴⁰ K, KF’s radioactivity is 20,979 Bq kg ⁻¹ , at 89.28% of beta radiation and to and 10.72% gamma radiation of 1,460 83 MeV .

Potassium fluoride can be prepared by dissolving excess potassium carbonate in fluorhydric acid. During the evaporation of the solution, potassium bifluoride crystals are formed. By heating this bifluoride you get potassium fluoride:

K ₂ CO ₃ + 4 HF _aq → 2 KHF ₂ + CO ₂ ↑ + H ₂ O

KHF ₂ → KF + HF↑

This salt obviously cannot be prepared in a glass or porcelain container because it would be attacked by flurohydrical acid. A plastic container (PTFE) resistant to heat or platinum should be used.

Chemistry [ modifier | Modifier and code ]

In organic chemistry, potassium fluoride can be used for the conversion of organochlorine compounds into organofluorés compounds, via the finkelstein reaction ^{[ 9 ]} . For such reactions we generally use a polar solvent such as dimethylformamide (DMF), glycol ethylene or dimethylsulfoxide (DMSO) ^{[ ten ]} .

Others [ modifier | Modifier and code ]

Potassium fluoride is used in enamel production, as an additive for cement, as an oxidant in the aluminum weld powder. It is also used as a wooden conservation agent and for glass engraving. It can also be used as a source of fluoride ions in oral hygiene products (toothpaste, mouthwash, etc.) and for fluoridated foods (food salt, water).

Like other sources of fluoride ions, KF is toxic, even if the lethal doses are of the gram level for humans. It is dangerous by inhalation and ingestion. It is highly corrosive, any contact with the skin that can cause severe burns.