Tin dichloride

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

other: modeling

Study period:

1939-2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Publication is a rewiew of measured data from 1939 to 1995 in the background of modeling tin in radioactive waste

Data waiving:

other justification

Justification for data waiving:

other:

Data source

Reference

Reference 1

Reference Type:

publication

Title:

A critical rewiev of thermodynamic data for inorganic tin species

Author:

Séby et al.

Year:

2001

Bibliographic source:

Geochimica et Cosmochimica Acta Vol. 65, 3041-3053, 2001

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1981

Reference 3

Reference Type:

publication

Title:

On the role of Sulfate Ion in Acid Tin Methansulfonate Electrolytes

Author:

Martyak et al.

Year:

2006

Bibliographic source:

Galvanotechnik 1/2006 p.46ff

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

not applicable

Remarks:

special methods see box "pronciples of methode if other than guideline"

Principles of method if other than guideline:

methodes used: potentiometry, Difference Pulse Cathodic Stripping Voltammetry, calculation, combination of thermodynamic formation data

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

21651-19-4

Cas Number:

21651-19-4

IUPAC Name:

21651-19-4

Constituent 2

Reference substance name:

18282-10-5

Cas Number:

18282-10-5

IUPAC Name:

18282-10-5

Constituent 3

Reference substance name:

Tin difluoride

EC Number:

231-999-3

EC Name:

Tin difluoride

Cas Number:

7783-47-3

Constituent 4

Reference substance name:

Tin dichloride

EC Number:

231-868-0

EC Name:

Tin dichloride

Cas Number:

7772-99-8

Molecular formula:

[Cl-].[Cl-].[Sn++]

IUPAC Name:

tin dichloride

Constituent 5

Reference substance name:

Tin dibromide

EC Number:

233-087-0

EC Name:

Tin dibromide

Cas Number:

10031-24-0

Constituent 6

Reference substance name:

Tin diiodide

EC Number:

233-667-3

EC Name:

Tin diiodide

Cas Number:

10294-70-9

Constituent 7

Reference substance name:

Tetrafluorostannane

EC Number:

232-016-0

EC Name:

Tetrafluorostannane

Cas Number:

7783-62-2

IUPAC Name:

tetrafluorostannane

Constituent 8

Reference substance name:

Tin tetrachloride

EC Number:

231-588-9

EC Name:

Tin tetrachloride

Cas Number:

7646-78-8

IUPAC Name:

tin(4+) tetrachloride

Constituent 9

Reference substance name:

Tin tetrabromide

EC Number:

232-184-5

EC Name:

Tin tetrabromide

Cas Number:

7789-67-5

IUPAC Name:

tin(4+) tetrabromide

Constituent 10

Reference substance name:

Tin tetraiodide

EC Number:

232-208-4

EC Name:

Tin tetraiodide

Cas Number:

7790-47-8

IUPAC Name:

tin(4+) tetraiodide

Radiolabelling:

no

Study design

Analytical monitoring:

not specified

Estimation method (if used):

modeling at standard conditions (temperature: 25°C, pressure: 1 bar, ionic strenght: 0) using SIT methodology

Results and discussion

Transformation products:

yes

Any other information on results incl. tables

Sédy et al. pointed out that in the most studies to high concentrations of tin were used and so polytin complexes were formed. Further Sédy et al. show that there is a different in the species formed in a solution with and without halogeninde.

The values measured under standard conditions (25°C, 1bar)

 

Chemical equilibrium	-log^{m}K°	I (mol L^{-})	Remark
Sn^{2+} + H_{2}O <=> SnOH^{+} + H^{+}	3.8 +/- 0.2	0.1, 0.5, 1.0	Inorganic tin hydrolysis
Sn^{2+} + 2H_{2}O  <=> Sn(OH)^{0}_{2} + 2H^{+}	7.8 +/- 0.2	0.1, 0.5, 1.0	Inorganic tin hydrolysis
Sn^{2+} +3H_{2}O  <=> SnOH^{-}_{3} + 3H^{+}	-17.5 +/- 0.2	0.1, 0.5, 1.0	Inorganic tin hydrolysis
Sn(OH)_{2}(s)óSn^{2+} + OH^{-}	25.80	0_{corr}	Precipitation Reactions
SnO(s) + H_{2}O   <=> Sn^{2+} + OH^{-}	26.24	0_{corr}	Precipitation Reactions

 

The ion interaction coefficients are:

%epsilon	Value (L mol^{-1}
Sn^{2+}, NO_{3}^{-}	0.4 +/- 0.1
SnOH^{+}, NO_{3}^{-}	0.2 +/- 0.1
Sn(OH)_{2}, NO_{3}^{-}	0.3 +/- 0.1
H^{+}, NO_{3}^{-}	0.07 +/- 0.01

 

 

Distribution of various species of tin (II) as a function of pH

	Sn^{2+} / %	Sn(OH)^{+} / %	Sn(OH)_{2} / %	Sn(OH)_{3}^{-} / %
4.0	30	40	30	0
4.5	7	34	59	0
5.0	2	11	87	0
5.5	0	4	96	0
6.0	0	2	98	0
6.5	0	1	99	0
7.0	0	0	100	0
7.5	0	0	99	1
8.0	0	0	98	2
8.5	0	0	95	5
9.0	0	0	80	20
9.5	0	0	50	50
10.0	0	0	30	70

 

Distribution of various species of tin (II) as a function of pH in present of 10^{-2} mol L^{-} [Cl^{-}]

	Sn^{2+} / %	SnCl^{+} / %	SnCl_{2} / %	Sn(OH)^{+} / %	Sn(OH)_{2} / %	Sn(OH)_{3}^{-} / %
4.0	27	10	1	35	27	0
4.5	8	3	0	29	60	0
5.0	0	0	0	15	85	0
5.5	0	0	0	5	95	0
6.0	0	0	0	3	97	0
6.5	0	0	0	1	99	0
7.0	0	0	0	0	100	0
7.5	0	0	0	0	99	1
8.0	0	0	0	0	98	2
8.5	0	0	0	0	95	5
9.0	0	0	0	0	80	20
9.5	0	0	0	0	50	50
10.0	0	0	0	0	30	30

 

recovery of data: 95%

Martyak reports for the hydrolysis reaction of stannos sulfate a free energy of %DELTA G = -7.37 kcal/mol and a equilibrium constant of ~1.8 x 10^5.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Tin(II) can be hydrolysed into SnOH^{+}, Sn(OH)_{2} and Sn(OH)^{-}_{3}. In The pH frame according the guideline most of the Sn(II) exists as
Sn(OH)_{2}. The equilibrium constant for the dissioziation logK = 7.8 +/- 0.2 (@20°C)..
Martyak reports for the hydrolysis reaction of stannos sulfate a free energy of %DELTA G = -7.37 kcal/mol and a equilibrium constant of ~1.8 x 10^5.

So the stannous sulfate ist not stable in water. Under alkaline conditions (pH>8 ) changes immediately oxidation state 2 to 4.