Potassium hexafluorosilicate

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  • Identifiers

    CAS number
    16871-90-2

    Molecular formula
    F6K2Si

    SMILES
    F[Si-2](F)(F)(F)(F)F.[K+].[K+]

    Safety labels

    Acute Toxic
    Acute Toxic

  • Odor profile

  • Properties

    Molecular weight
    220.272 g/mol

    Solubility expt.

    • Solubility in water, g/100ml at 20 °C: 0.18 (poor)

  • Synonyms

    • Potassium hexafluorosilicate
    • 16871-90-2
    • Potassium fluosilicate
    • Potassium silicofluoride
    • Dipotassium hexafluorosilicate
    • 2610W49XYD
    • Dipotassium hexafluorosilicate(2-)
    • EINECS 240-896-2
    • UN2655
    • UNII-2610W49XYD
    • Silicate(2-), hexafluoro-, potassium (1:2)
    • DTXSID10884939
    • POTASSIUM HEXAFLUOROSILICATE [MI]
    • SILICATE, HEXAFLUORO-, DIPOTASSIUM
    • EC 240-896-2
    • RefChem:175487
    • FLUOSILICATE DE POTASSIUM
    • Dipotassium hexafluorosilicate(2)
    • FLUOROSILICATE DE POTASSIUM
    • SILICOFLUORURE DE POTASSIUM
    • DTXCID001024356
    • Silicate(2), hexafluoro, dipotassium
    • Silicate(2), hexafluoro, potassium (1:2)
    • POTASSIUM FLUOROSILICATE
    • dipotassium;hexafluorosilicon(2-)
    • Silicate(2-), hexafluoro-, dipotassium
    • MFCD00040666
    • F6K2Si
    • UUHPPUWEDCVPCO-UHFFFAOYSA-N
    • Dipotassium hexafluoridosilicate(2-)
    • AKOS015914459
    • NS00085156
    • Potassium hexafluorosilicate, >=99.0% (T)
    • Potassium fluorosilicate [UN2655] [Poison]
    • Q4134938
    • 16871-90-2

  • Applications

    Potassium hexafluorosilicate (CAS 16871-90-2) is used as a fluoride source and flux in high-temperature metalworking, including brazing and soldering, and as a glaze additive and etchant in glass and ceramic processing; it also serves as a precursor or intermediate in the synthesis of fluoride-containing inorganic materials; it can appear in specialty cleaning formulations for metal surfaces where fluoride activity aids oxide removal; and may serve as a fluorine donor in certain glaze, enamel, and coating formulations. Subject to local regulations and formulation limits.

    gpt-5-nano

1 4

IFRA standard 51

Recommendation
No restriction
Maximum acceptable concentrations in the finished product (%)
Category 1
Products applied to the lips
 No restriction Category 7A
Rinse-off products applied to the hair with some hand contact
 No restriction
Category 2
Products applied to the axillae
 No restriction Category 7B
Leave-on products applied to the hair with some hand contact
 No restriction
Category 3
Products applied to the face/body using fingertips
 No restriction Category 8
Products with significant anogenital exposure
 No restriction
Category 4
Products related to fine fragrance
 No restriction Category 9
Products with body and hand exposure, primarily rinse off
 No restriction
Category 5A
Body lotion products applied to the body using the hands (palms), primarily leave on
 No restriction Category 10A
Household care products with mostly hand contact
 No restriction
Category 5B
Face moisturizer products applied to the face using the hands (palms), primarily leave on
 No restriction Category 10B
Household care products with mostly hand contact, including aerosol/spray products (with potential leave-on skin contact)
 No restriction
Category 5C
Hand cream products applied to the hands using the hands (palms), primarily leave on
 No restriction Category 11A
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate without UV exposure
 No restriction
Category 5D
Baby Creams, baby Oils and baby talc
 No restriction Category 11B
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate with potential UV exposure
 No restriction
Category 6
Products with oral and lip exposure
 No restriction Category 12
Products not intended for direct skin contact, minimal or insignificant transfer to skin
 No restriction