Atomistry » Chromium » Compounds » Chromium Silicofluoride
Atomistry »
  Chromium »
    Compounds »
      Chromium Silicofluoride »

Chromium Silicofluoride, Cr2F6.(SiF4)3

Chromium Silicofluoride, Cr2F6.(SiF4)3, is obtained in solution when chromium sesquioxide is dissolved in hydrofluosilicic acid.6 It has not yet been isolated, since in aqueous solution it undergoes decomposition; the violet solution spontaneously and gradually becomes bluish green, and silicon tetrafluoride is liberated, thus:

Cr2F6.(SiF4)3 = SiF4 + Cr2F6.(SiF4)2,

the silicon tetrafluoride then being decomposed by water. On evaporation more silicon tetrafluoride is liberated, and a green hydrated fluoride can be isolated, to which Recoura gives the formula (CrF.5H2O)SiF6, considering it analogous to the two silicofluorides prepared by Jorgensen, of composition (CrCl.5NH3)SiF6 and (CrCl.4NH3.H2O)SiF6.

The freshly prepared violet solution of chromium silicofluoride reacts with potassium chloride, thus:

Cr2F6.(SiF4)3 + 6KCl = 3K2SiF6 + 2CrCl3;

but if the solution has been allowed to stand, the products are potassium silicofluoride and a compound, (Cr2F2)Cl4, from which the fluorine cannot be precipitated by adding barium chloride.

The hydrated compound (CrF.5H2O)SiF6 is stable in dry air or in a vacuum; but in contact with moist air it slowly loses silicon tetra- fluoride, and ultimately yields hydrated chromic fluoride, Cr2F6.7H2O.

Last articles

Tb in 6TVY
Si in 6Y7O
Rh in 6WRM
Rh in 6WRL
Ni in 6Y8Z
Ni in 6Y8Y
Na in 6ZXZ
Na in 7ACG
Na in 6YLS
Na in 6Y8Z
© Copyright 2008-2020 by atomistry.com
Home   |    Site Map   |    Copyright   |    Contact us   |    Privacy