Stannous fluoride

Tin(II) fluoride

Sn2+;      F−
Names
IUPAC name Tin(II) fluoride
Other names Stannous fluoride
Identifiers
CAS Number	7783-47-3 Y
3D model (Jmol)	Interactive image
ECHA InfoCard	100.029.090
PubChem	24550
RTECS number	XQ3450000
UN number	3288
InChI InChI=1S/2FH.Sn/h2*1H;/q;;+2/p-2
SMILES F[Sn]F
Properties
Chemical formula	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)
Solubility in water	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
Crystal structure	Monoclinic, mS48
Space group	C2/c, No. 15
Pharmacology
ATC code	A01AA04 (WHO)
Hazards
Safety data sheet	ICSC 0860
NFPA 704	0 2 0
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 YN ?)
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 Sn^IV, which are ineffective as a dental prophylactic. Studies of the oxidation using Mössbauer spectroscopy on frozen samples suggests that O₂ is the oxidizing species.