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CHEMISTRY : Metal Cation Identification


PROJECT TITLE: ID of ZIRCONIUM Cations by Precipitation Reactions
LAST UPDATE: 15-Jul-98
VERSION HISTORY: 1.0 ( Context updates)
V2.0 ( Text and formatting update - Sep-2009)


This is an account on how to detect Zirconium ions in solution by simple precipitation reactions. Zirconium is very easy to distinguish since it has many of its compounds in the solid form, hence precipitate from solution. However, most of these are white in colour. With the following set of tests it will be easy to confirm Zirconium without requiring complex procedures or sophisticated equipment. It should ne noted that Zirconium and it's compounds are very poisoinous substances and great care should be taken in performing such tests.


As mentioned, the tests are simple precipitation reactions. A solution of a Zirconium salt (Mercury(II) Sulphate) was mixed with an equal ammount of another solution, in which a physical change is noted, usually a colour change due to a precipitation of the Zirconium insoluble compound or formation of a complex since Zirconium is a transitional metal.

Zr4+ X4- (aq) + 4 Na+ Y- (aq) ===> Zr4+ Y4- (s) + 4 Na+ X- (aq)
(s) Solid precipitate forming a colour change in soultion

One type of reaction is not enough, to confirm the presence of Zirconium, since other metal salts can give the same results. The verification of 4 or 5 such tests will be enough to confirm Zirconium in an unknown sample.


In 10ml testtubes, 4mls of Zirconium solution was placed. To this about 2mls of The following compounds all having different anions (-ve) was added. If desired, the mixture was heated gently to increase rate of reaction or added in exess to detect further complex reactions, usually the dissolving of the ppt just formed.
The following compounds were mixed with the Zirconium salt of which 24 produced a valuable result. These are marked with an Y in the React Column .
01 Sodium Hydroxide Y
02 Ammonium Hydroxide Y
03 Sodium Carbonate Y
04 Potassium Sulphate Y
05 Sodium ThioSulphate Y
06 Sodium (Metabi)Sulphite Y
07 Sodium Sulphide Y
08 Sodium Fluoride
09 Sodium Chloride
10 Potassium Bromide
11 Ammomium Iodide
12 Potassium Iodate Y
13 Ammonium Phosphate Y
14 Sodium TetraBorate (Borate) Y
15 Sodium Salicylate Y
16 Sodium Benzoate
17 Tannic Acid
18 Sodium Malate sol. Y
19 Sodium Methanoate sol. Y
20 Sodium Ethanoate
21 Sodium Citrate Y
22 Sodium Tartarate Y
23 Sodium Silicate Y
24 Potassium Ferro(II)Cyanide Y
25 Potassium Ferri(III)Cyanide Y
26 Sodium Vanadate Y
27 Potassium Permanganate
28 Potassium Dichromate Y
29 Sodium Tungstate Y
30 Ammonium Molybdate Y
31 Sodium BiSelenite Y
32 Potassium Thiocyanate


01: Sodium Hydroxide

a) A GELATINOUS WHITE ppt was formed, insoluble in xs.

b) On heating no colour change took place. The insoluble Zirconium Hydroxide was precipitated.

02: Ammonium Hydroxide

a) This also gave a GELATINOUS WHITE ppt, being insoluble in xs.

b) No further reaction on heating or standing

The hydroxide was preipitated by Ammonia

03: Sodium Carbonate

a) A DENSE WHITE ppt soluable in xs was obtained

b) Heating the dense white ppt gave no change, but heating the colourless solution obtained by xs carbonate yielded back a white ppt. Precipitation of Zirconium Carbonate.

04: Potassium Sulphate

a) A WHITE ppt formed slowly (in about 10 seconds)

b) On heating, the white ppt increased forming a MILKY WHITE ppt

The Zirconium Sulphate could have been ppt here.

05: Sodium Thiosulphate

a) A WHITE ppt formed very slowly (in about 30 sec)

b) On heating, the white ppt was formed faster resulting in a MILKY WHITE/CREAM ppt. The Zirconium Thiosulphate could have been ppt here.

06: Sodium Sulphite (or Sodium Metabisulphite)

a) On adding the sulphite dropwise, A WHITE PPT which dissolved in the xs zincorium was formed. On adding further sulphite in xs, the ppt did not dissolved further, resulting in a WHITE ppt.

b) No change on heating. With Zr salt in xs, a complex could have been formed, but in xs sulphite, precipitation of the insoluble Zincorium Sulphite took place.

07: Sodium Sulphide

a) A DENSE WHITE ppt was formed.

b) No further reactions on heating, or standing out. Zirconium Sulphide was ppted at once.

08: Sodium Fluoride

a) GELATINOUS/TRANSPERENT white ppt was formed.

b) No reaction on heating, apart from becoming more whitish

One of the few definite ppt with a fluoride, hence Zincorium fluoride.

09: Potassium Iodate

a) A DENSE WHITE/CREAM PPT was immediately formed.

b) No further reaction on heating. Zircorium Iodate was precipitated out.

10: Ammonium Phosphate

a) A DENSE WHITE ppt was formed.

b) On heating, no further reaction took place. Zircorium Phosphate was precipitated out.

11: Sodium TetraBorate

a) No reaction initially, but with xs a white ppt was obtained

b) No further reaction on heating. Zirconium Borate was precipitated out, after initially forming a sort of soluble complex ion.

12: Sodium Salicylate

a) THICK MILKY white ppt.

b) No further reaction on heating

Zirconium Salicylate was precipitated out on heating.

13: Sodium Malate Solution

a) A WHITE ppt soluble in xs was obtained

b) No effect on heating. One of the few reactions with the malate anion. Precipitation followed by complex ion formation took place here.

14: Sodium Methanoate

a) A WHITE ppt insoluble in xs was obtained.

b) No reaction on heating

The Zirconium Methanoate was precipitatd.

15: Sodium Citrate

a) A WHITE ppt very soluble in xs was obtained

b) No effect on heating. One of the few reactions with the citrate anion. Precipitation followed by complex ion formation took place here.

16: Sodium Tartarate

a) A MILKY WHITE ppt only after adding xs tartarate.

b) On heating the ppt formed immediately. Another few reactions which took place with the Tartarate. Propably the precipitation of Zincorium tartarate.

17: Sodium Silicate

a) A THICK GELATINOUS PPT on adding xs silicate.

b) No further reaction on heating or standing

Zirconium Silicate was precipitated.

18: Potassium Ferro(II)Cyanide

a) A CREAM/WHITE ppt was formed.

b) On heating, a BLUE/CYAN ppt was obtained. This was not filterable, (against that obtained with mercury!)

Complex reaction, see below.

19: Potassium Ferri(III)Cyanide

a) No reaction initially.

b) DARK OLIVE GREEN ppt was formed on heating. On filtering, clear green solution + dark green ppt was obtained. Another complex reaction, but the acid in solution might have interfered (contributed to the green sol.) since it gives the similar results when acid is added to ferro(iii)cyanide and heated as a control.

20: Sodium Vanadate

a) A YELLOW solution was immediately formed. On xs, a YELLOW precipitate was formed. On filtering a clear YELLOW solution + YELLOW ppt was resulted.

b) No particular change on heating. Complex reaction, perhaps the Vanadium salt (yellow solution) and the Zirconium Vanadate precipitation were formed ?!?

21: Potassium Dichromate

a) No reaction initially.

b) On heating, a YELLOW ppt was formed, which on filtering a DEEP YELLOW ppt + a clear YELLOW solution was formed. The latter may be xs dichromate solution. One of the few precipitates formed by potassium dichromate.

22: Sodium Tungstate

a) A THICK MILKY WHITE ppt was obtained

b) No effect on heating. Precipitation of white Zincronium Tungstate

23: Ammonium Molybdate

a) A MILKY WHITE ppt resulted.

b) No further changes on heating. Formation of the solid Zirconium Molybdate

24: Sodium Biselenite

a) A DENSE MILKY WHITE ppt was formed

b) No further reactions on heating

White Zirconium Selenite ppt was formed.


Zirconium is a transitional metal, and forms many precipitates, which however most of them are white in colour, including the sulphide, which usually always form dark ppts.

It forms a gelatinous white ppt with the Sodium Hydroxide, and Ammonium Hydroxide, both insoluble in xs. Zincorium is also the only metal which dissloves forms a GELATINOUS WHITE precipitate with Sodium Carbonate which dissolves to a colourless solution when added in xs.

The colourful precipitates obtained are with the Ferro(II)Cyanide, which makes a cream white ppt which turns Cyan on heating. This is very similar to mercury though. With Ferri(III)Cyanide an olive green ppt is obtained on heating. Also a yellow ppt is formed with the Dichromate (on heating) and with Vanadate (in xs). Yellow Lead dichromate is produced immediately without need of heeting.

Other unique white precipitates are those with the Tartarate, Salicylate, Methanoate, Citrate, and Malate the last two being soluble in xs. The Sulphate, thioSulphate, Sulphide forms also white precipitates.

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