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The hydrogen chromate ion, HCrO 4 −, is a weak acid: HCrO − 4 ⇌ CrO 2− 4 + H +; pK a ≈ 5.9. It is also in equilibrium with the dichromate ion: 2 HCrO − 4 ⇌ Cr 2 O 2− 7 + H 2 O. This equilibrium does not involve a change in hydrogen ion concentration, which would predict that the equilibrium is independent of pH.
Chromate and dichromate have equal concentrations. Setting [CrO 2− 4] equal to [Cr 2 O 2− 7] in Eq. 3 gives [CrO 2− 4] = 1 / β 2 [H +] 2 . The predominance diagram is interpreted as follows. The chromate ion is the predominant species in the region to the right of the green and blue lines. Above pH ~6.75 it is always the ...
This is a list of common chemical compounds with chemical formulae and CAS numbers, indexed by formula. This complements alternative listing at list of inorganic compounds . There is no complete list of chemical compounds since by nature the list would be infinite.
Sodium dichromate is the inorganic compound with the formula Na 2 Cr 2 O 7.However, the salt is usually handled as its dihydrate Na 2 Cr 2 O 7 ·2H 2 O.Virtually all chromium ore is processed via conversion to sodium dichromate and virtually all compounds and materials based on chromium are prepared from this salt. [1]
Ammonium dichromate is an inorganic compound with the formula (NH 4) 2 Cr 2 O 7. In this compound, as in all chromates and dichromates, chromium is in a +6 oxidation state, commonly known as hexavalent chromium. It is a salt consisting of ammonium ions and dichromate ions.
ion has a similar radius (63 pm) to Al 3+ (radius 50 pm), and they can replace each other in some compounds, such as in chrome alum and alum. Chromium(III) tends to form octahedral complexes. Commercially available chromium(III) chloride hydrate is the dark green complex [CrCl 2 (H 2 O) 4]Cl.
sodium chromate Na 2 CrO 4 is made yellow by the chromate ion CrO 2− 4. potassium dichromate K 2 Cr 2 O 7 is made red-orange by the dichromate ion Cr 2 O 2− 7. cobalt(II) nitrate hexahydrate Co(NO 3) 2 ·6H 2 O is made red by the chromophore of hydrated cobalt(II) [Co(H 2 O) 6] 2+. copper(II) sulfate pentahydrate CuSO 4 ·5H 2 O is made ...
Download as PDF; Printable version; ... Silver dichromate is a chemical compound with the formula Ag 2 Cr 2 O 7.