*** Welcome to piglix ***

Stannous fluoride

Tin(II) fluoride
Kristallstruktur Zinn(II)-fluorid.png
     Sn2+;      F
Names
IUPAC name
Tin(II) fluoride
Other names
Stannous fluoride
Identifiers
7783-47-3 YesY
3D model (Jmol) Interactive image
ECHA InfoCard 100.029.090
PubChem 24550
RTECS number XQ3450000
UN number 3288
Properties
SnF2
Molar mass 156.69 g/mol
Appearance colorless solid
Density 4.57 g/cm3
Melting point 213 °C (415 °F; 486 K)
Boiling point 850 °C (1,560 °F; 1,120 K)
31 g/100 mL (0 °C);
35 g/100 mL (20 °C);
78.5 g.100 mL (106 °C)
Solubility soluble in KOH, KF;
negligible in ethanol, ether, chloroform
Structure
Monoclinic, mS48
C2/c, No. 15
Pharmacology
A01AA04 (WHO)
Hazards
Safety data sheet ICSC 0860
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Related compounds
Other anions
Tin(II) chloride,
Tin(II) bromide,
Tin(II) iodide
Other cations
Germanium tetrafluoride,
Tin tetrafluoride,
Lead(II) fluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

Tin(II) fluoride, commonly referred to commercially as stannous fluoride (from Latin stannum, 'tin') is a chemical compound with the formula SnF2. It is a colorless solid used as an ingredient in toothpastes that are typically more expensive than those that use sodium fluoride. Stannous fluoride converts the calcium mineral apatite into fluorapatite, which makes tooth enamel more resistant to bacteria-generated acid attacks. In toothpastes containing calcium minerals, sodium fluoride becomes ineffective over time, while stannous fluoride remains effective in strengthening tooth enamel. Stannous fluoride has been shown to be more effective than sodium fluoride in reducing the incidence of dental caries and controlling gingivitis.

Stannous fluoride was used under the trade name Fluoristan in the original formulation of the toothpaste brand Crest, though it was later replaced with sodium monofluorophosphate under the trade name Fluoristat. It is the active ingredient in Crest Pro Health brand toothpaste. Crest Pro Health issues a warning on the tube that stannous fluoride may cause staining, which can be avoided by proper brushing, and that its particular formulation is resistant to staining. However, any stannous fluoride staining that occurs due to improper brushing is not permanent. Stannous fluoride is also used in Oral-B Pro-Expert. Stannous fluoride is also readily available in over-the-counter rinses.

SnF2 can be prepared by evaporating a solution of SnO in 40% HF.

Readily soluble in water, SnF2 is hydrolysed. At low concentration, it forms species such as SnOH+, Sn(OH)2 and Sn(OH)3. At higher concentrations, predominantly polynuclear species are formed, including Sn2(OH)22+ and Sn3(OH)42+. Aqueous solutions readily oxidise to form insoluble precipitates of SnIV, which are ineffective as a dental prophylactic. Studies of the oxidation using Mössbauer spectroscopy on frozen samples suggests that O2 is the oxidizing species.


...
Wikipedia

...