Potassium-chrome alum

If more than simple atoms are bound to a central atom, then the coordination number still refers to the number of near neighbors. For example, in solid potassium chrome alum, KCr(S04)2- 12H20, and also in its fresh aqueous solutions, the chromium-containing cation is... [Pg.393]

As an example of the problem of species in solution, consider the case of a solution made by dissolving some potassium chrome alum, KCrfSO s-12H20, in water. On testing, the solution is distinctly acidic. A currently accepted explanation of the observed acidity is based upon the assumption that, in water solution, chromic ion is associated with six H20 molecules in the complex ion, Cr(H20) a. This complex ion can act as a weak acid, dissociating to give a proton (or hydronium ion). Schematically, the dissociation can be represented as the transfer of a proton from one water molecule in the Cr(H20) 3 complex to a neighboring H20 to form a hydronium ion, H30+. Note that removal of a proton from an H20 bound to a Cr+3 leaves an OH- group at that position. The reaction is reversible and comes to equilibrium ... [Pg.396]

Probably the most common compound of +3 chromium is potassium chrome alum, KCr(SOi)r 12H20. We know that the twelve water molecules are distributed equally, six around Cr+a and six around K+. Potassium chrome alum is just one example of the general class of solids called alums which have a 4-1 ion, a +3 ion, two sulfates, and twelve molecules of water. In the dyeing industry chrome alum is used for fixing dyes to fabrics. [Pg.403]

Potassium chrome alum, 393 Potassium permanganate, 218 Potential energy, 115 barrier, 134... [Pg.464]

I947) 294 3)Kirk Othmer 1 (1947), 655 4)Cond Chem Dict(1956), 52 Potassium-Chrome Alum(Chrome Alum),... [Pg.156]

Twelve grams of potassium thiocyanate are heated very gently in an evaporating dish until the salt just begins to melt, around 170°C. Gentle heating is continued while lOg of finely powdered potassium chrome alum is sifted onto... [Pg.89]

Chrome Potash Alum. See Potassium-Chrome Alum, Vol 1, pl56-R... [Pg.81]

Potassium Amide or Potassamide A169-R Potassium Azide A594-R Potassium Azidodithiocarbonate A634-L Potassium Carbide A79-L Potassium Chrome Alum. See under Alums A156-R... [Pg.689]

Crystals of potassium chrome-alum, potassium chromium sulphate, or potassium... [Pg.333]

Figs. 84 and 85.—Absorption Spectra of Solutions of Potassium Chrome-Alum. [Pg.338]

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