Home
Introduction
Search Menu
IUPAC Series (PDF)
Reference
Version History
About the Project
Disclaimer
Contact Us
Acknowledgements
IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Lanthanum formate with Cerium formate, Praseodymium formate and Water
Components:
(1) Cerium formate; Ce(CHO2)3; [3252-51-5]
NIST Chemistry WebBook
for detail
(2) Lanthanum formate; La(CHO2)3; [2081-11-0]
NIST Chemistry WebBook
for detail
(3) Praseodymium formate; Pr(CHO2)3; [3252-52-6]
NIST Chemistry WebBook
for detail
(4) Water; H2O; [7732-18-5]
NIST Chemistry WebBook
for detail
Original Measurements:
Plyushchev, V.E.; Shklover, P.P.; Shkolnikova, L.M.; Kuznetsova, C.P.; Nadezhdina, G.V., Dokl. Acad. Nauk SSSR 160, 366-9 (1965).
Variables:
Temperature = 25 ºC to 50 ºC
Prepared By:
Chr. Balarew and St. Trendafilova
Experimental Remarks:
The molality values were calculated by the compilers.
Authors' Comment:
The solubility is expressed as % oxide because at 50 °C, hydrolysis possibly occurs. Analysis of crystal phases dried at room temperature shows a composition Me(CHO
2
)
3
·
n
H
2
O where
n
= 0-0.5 for the formates from La to Ho. However the presence of water could not be confirmed by IR spectroscopy. For Eu and Gd,
n
= 0.
Experimental Data:
(Notes on the Nomenclature)
(Please see footnotes following the table(s).)
Part 1. Solubility polytherm of the La(CHO
2
)
3
-H
2
O system.
t/°C
Chemical
1
Phase
Mass Fraction w
1
m
1
[mol kg-1]
Chemical
2
Mass Fraction w
2
m
2
[mol kg-1]
Solid Phase(s)
a
25
La2O3
Liquid
0.19
0.006
La(CHO2)3
0.32
0.0117
A
40
La2O3
Liquid
0.19
0.006
La(CHO2)3
0.32
0.0117
A
50
La2O3
Liquid
0.19
0.006
La(CHO2)3
0.32
0.0117
A
Part 2. Solubility polytherm of the Ce(CHO
2
)
3
•0.2H
2
O-H
2
O system.
t/°C
Chemical
1
Phase
Mass Fraction w
1
m
1
[mol kg-1]
Chemical
2
Mass Fraction w
2
m
2
[mol kg-1]
Solid Phase(s)
a
25
Ce2O3
Liquid
0.20
0.006
Ce(CHO2)3
0.34
0.012
B
40
Ce2O3
Liquid
0.19
0.006
Ce(CHO2)3
0.32
0.012
B
50
Ce2O3
Liquid
0.19
0.006
Ce(CHO2)3
0.32
0.012
B
Part 3. Solubility polytherm of the Pr(CHO
2
)
3
-H
2
O
t/°C
Chemical
1
Phase
Mass Fraction w
1
m
1
[mol kg-1]
Chemical
2
Mass Fraction w
2
m
2
[mol kg-1]
Solid Phase(s)
a
25
Pr2O3
Liquid
0.24
0.007
Pr(CHO2)3
0.40
0.015
C
40
Pr2O3
Liquid
0.26
0.008
Pr(CHO2)3
0.44
0.016
C
50
Pr2O3
Liquid
0.26
0.008
Pr(CHO2)3
0.44
0.016
C
Notes:
a
The solid phases are: A = La(CHO
2
)
3
; B = Ce(CHO
2
)
3
•0.2H
2
O; C = Pr(CHO
2
)
3
.
Method/Apparatus/Procedure:
The isothermal method was used. The mixtures were stirred for one week. La
3+
and Ce
3+
were determined gravimetrically as La
2
O
3
and Ce
2
O
3
, respectively. Pr
3+
was pptd as Pr
2
(C
2
O
2
)
3
and the excess H
2
C
2
O
2
was back titrated with KMnO
4
. The solid phases were analyzed by DTA and IR spectroscopy.
Source and Purity of Materials:
The lanthanum salt was prepared by the reaction of freshly pptd La(OH)
3
with formic acid. Ce(CHO
2
)
3
•0.2H
2
O was obtained by the reaction of Ce2(CO
3
)
3
with formic acid. Pr(CHO
2
)
3
was obtained by reacting freshly pptd Pr(OH)
3
with formic acid. The Pr
2
O
3
had 0.05-1.5 mass% impurities. The formic acid has n
D
20
= 1.3712.
Estimated Errors:
Temperature: The temperature was controlled to within ±0.1 °C.