CR 0 AT IC A CHEM I CA ACT A 29 (1957) 49'

KRATKA SAOPCENJA SHORT COMMUNICATIONS

~CA-53 546.841-86 ; 541.123.5

The Determination of the Charge of Some Inorganic Thorium Complexes with the Ion - exchange Method

K. F . Schulz and M. J. Herak

Institute for Medical Research, Yugoslav Academy of Sciences and Arts, and

Institute »Ruder Boskovic« Zagreb, Croatia, Yugoslavia

Received March 8, 1957

Chemistry of ilhorirum complexes •is now of particular interest but O'\l["

knowledge is still inadequate. The thorium i.on forms various coplexes with a great number of anions and in water sofotions the salts of thorium are undergoing hydTolysis already at low pH values (pH>· 3.5)' giving various products.

In connection with our investig,atiorus it has been o f gveat interest for us to know the composition .and charge of the thorium complexes of chloride, nitrate, and sulphate in the concentration ·reg,ion from 0.1-5 M . At .the same time we wished to know whether presence o.f other cations has any influence on the formation of th ese complexes.·

Day and Stoughton1 1and ZEibTOski, Alter and Heumann2 have investigated ihe formation of thnrium complexes with these aniooo using the solvent extraction method with thenoyltrifluoroacetone as the chelating agent in the presence of high concentra tions of rperchloTate ions. They have found that all inV·ffitigated anions (F- ' c1- 'N0:1- ' so4- ' po~- ' etc.) form complex thorium

ions of the type ThX~+ . In the ipresent investigation we have .applied the ion-exchange method

given by Striokland3 aTIJd Kr.a1U.s and Ne1son4. Alpplying the law of mass adion to the ion eX'chlange processes Krauss and Nelson obtained a simple relationship

dlogD v =

where D is the distrilbution ooefficient, i. e. the ratio between the concen­tr.wtion of the investigated ion in the ion excha:nger phase and in the solution phase.

C,. is the concentrntion of the known charge ion (the exchanging ion) in the solution .ait equilibrium.

a iis the charge orf the exchanging ion. v is the charge of the complex i01ll.

50 K. F. SCHULZ AND M. J: HERAK

EXPERIMENTAL

The ion-exchanger used was Amberlite IR-120 (60-100 Mesh) transferred into­the exchanging ion form by treatment in the column. The systems were prepared. in glass-stoppered reagent bottles of 50 ml., giving a determined volume of the· thorium nitrate solution 1.36 X 10-a M to which had been added the solution of Th234 (N03)4 (carrier free) and the solution of the exchanging ion. The total volume was always 10 ml. 0.25 g. of the air dried resin were added, the · systems kept for 24 hours at room temperature and then the activity of Th-234 was measured in 2 ml. of supernatant liquid with a G. M. counter. The thorium-234 was isolated. from the solution of uranyl nitrate by the method described by Dyrssens.

0

1 - NaCl 2 -HCI

3" -LICI 3 6 -KCI

- ---'--++-'T--- 4 : M!!CI, --

5 -eac1,

0

LOG CONC !¥Cl INI

0

§

LOG CONC MeNO, tNl

Fig. 1. Fig. 2. Fig. 1. Determination of charge of thorium chloride c omplex ions in solutions of NaCl, HCl,

LiCl, KC!, MgC!,, and Caci,. Fig. 2. D et e rmination of charge of thorium nitrate complex ions m solutions of NaNO., HNOs,

LiNOa, Mg(N0s)2, and Ca(N03)!.

RESULTS

We haive detel'!Ilined the charge of complex thorium chlOTide ions in the· following solutions of eledrolytes: Na.Cl, HCl, LiCl, KCl, MgC12, and CaCl2

respectively. In Fig. 1 the values of log D .are plotted against the logarithm of concentrations o.f the exchanging ion in :solution. It can be seen that the slope of the straight lines is for monovaleint exchanging i001S -2, and for divalent -1. Thus the charge ·o.f tho["ium chfoiride complex ion would be 2 +, what may indicate prevalence of complex ThCl/+. It is interesting to note that there was. no difference between neutral and acid solutions.

The results oihtained in nitrate media for NaiN03 , HN03 , LiN03 , Mg(N03 ) 2 ,

and Ca(N03) 2 , are shown in fig. 2. The slopes of the straight lines in this case

CHARGE OF INORGANIC THORIUM COMPLEXES 51

are also -2 for mon01Valent ions and -1 for divalent ions, whioh sugigests that the prevalent complex ion has the ohaJ:ige of 2 +. The only deviation. from the i'eSult.s was obtained with the Mgi(N03) 2 solution, whexe from the slope of -2. one may oondrude rthat the charge i:s 4+.

In the presence of the :sulphate ·ion the slope of the straigh lines for all .exchanging ions indicates the cha'I"ge of 3+ for the complex Th(HS04) 3+ (Fiig. 3).

0

§

1 -H1SO• 2 •-IN~

26- NaiSO. 3 - MgSO..

a

LOG. CONC - MeSO,. INI

Fig. 3. Determination of charge of thorium sulphate complex ions in solutions of H2SO•. (NH,)2SO,, Na2S04, and Mgso •.

REFERENCES

1. R. A . Day and R .W. Stoughton, J. Am. Chem. Soc. 72 (1950) 5662. 2. E . L. Z e bro ski, H . W· A 1 t er and F .K. Heumann, J . Am. Chem. Soc. 73

(1951) 5646. : "~ :il: ! 3. J. D . H. Strick 1 and, Nature 169 (1952) 620, 738. 4. K. A. Kraus and F. Ne 1 son, Proc. Inter. Conf. Peaceful Uses Atomic Energy.

Vol. 7. New York 1956· P . 113. 5. D. Dy r s s en, Svensk Kem. Tidskr. 62 (1950) 153.

IZVOD

Odredivanje naboja nekih anorganskih torijevih kompleksa primjenom metode ionske izmjene

K. F. Schulz i M. J . Herak

Odredivan je naboj torijevih kompleksnih iona s kloridom, nitratom i sul:l'atom u prisutnosti razlicitih kationa pomocu ionske izmjene upotrebljujuCi torij-234 kao radioaktivni indikator.

52 K . F. SCHULZ AND M. J . HERAK

Nadeno je, ·da torij (IV) s kloridima u danim uvjetima tvori kompleks s 2 pozi­tivna naboja. S nitratima tvori u vecini slueajeva kompleks s 2 -pozitivna naboja jedino u otopini magnezijeva nitrata odreden je naboj 4+. Sulfatni ion u otopinama svih upotrebljenih elektrolita dao je kompleks s nabojem 3 +.

INSTITUT ZA MEDICINSKA ISTRA:ZIV ANJA JUGOSLAVENSKE AKADEMIJE ZNANOSTI I UMJETNOSTI

i INSTITUT »RUDER BOSKOVIC«

ZAGREB

Primlteno 8. o~uj ka 19i7~