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IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Neodymium formate with Samarium formate, Europium formate and Water
Components:
(1) Europium formate; Eu(CHO2)3; [3252-55-9]
NIST Chemistry WebBook
for detail
(2) Neodymium formate; Nd(CHO2)3; [3252-53-7]
NIST Chemistry WebBook
for detail
(3) Samarium formate; Sm(CHO2)3; [3252-54-8]
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:
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 Nd(CHO
2
)
3
-H
2
O system.
t/°C
Chemical
1
Phase
Mass Fraction w
1
m
1
[mol kg-1]
a
Chemical
2
Mass Fraction w
2
a
m
2
[mol kg-1]
a
Solid Phase(s)
b
25
Nd2O3
Liquid phase
0.24
0.007
Nd(CHO2)3
0.40
0.014
A
40
Nd2O3
Liquid phase
0.26
0.008
Nd(CHO2)3
0.43
0.015
A
50
Nd2O3
Liquid phase
0.26
0.008
Nd(CHO2)3
0.43
0.015
A
Part 2. Solubility polytherm of the Sm(CHO
2
)
3
-H
2
O system.
t/°C
Chemical
1
Phase
Mass Fraction w
1
m
1
[mol kg-1]
a
Chemical
2
Mass Fraction w
2
a
m
2
[mol kg-1]
a
Solid Phase(s)
b
25
Sm2O3
Liquid phase
0.47
0.014
Sm(CHO2)3
0.77
0.027
B
40
Sm2O3
Liquid phase
0.49
0.014
Sm(CHO2)3
0.80
0.028
B
50
Sm2O3
Liquid phase
0.48
0.014
Sm(CHO2)3
0.79
0.028
B
Part 3. Solubility polytherm of the Eu(CHO
2
)
3
-H
2
O system.
t/°C
Chemical
1
Phase
Mass Fraction w
1
m
1
[mol kg-1]
a
Chemical
2
Mass Fraction w
2
a
m
2
[mol kg-1]
a
Solid Phase(s)
b
25
Eu2O3
Liquid phase
0.25
0.007
Eu(CHO2)3
0.407
0.014
C
40
Eu2O3
Liquid phase
0.64
0.018
Eu(CHO2)3
1.042
0.037
C
50
Eu2O3
Liquid phase
0.29
0.008
Eu(CHO2)3
0.472
0.017
C
Notes:
a
These values were calculated by the compilers.
b
The solid phases are: A = Nd(CHO
2
)
3
; B = Sm(CHO
2
)
3
; C = Eu(CHO
2
)
3
.
Method/Apparatus/Procedure:
The isothermal method was used. The mixtures were stirred for one week. Eu
3+
was determined complexometrically.
1
Nd
3+
and Sm
3+
were determined gravimetrically as Nd
2
O
3
and Sm
2
O
3
, respectively. The solid phases were analyzed by DTA and IR spectroscopy.
Source and Purity of Materials:
The formate salts were prepared by reacting the respective hydroxide with formic acid. The Nd
2
O
3
, Sm
2
O
3
and Eu
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.
References:
1
L. I. Martinenko, Nauchn. Dokl. Vyssh. Shk. Khim. Khim. Tekhnol.
N4
, 718 (1958).