Compilation - Lanthanum formate with Cerium formate, Praseodymium formate and Water (IUPAC SDS Volume 73)
SDS Volume (4789)
Volume 73. Metal and Ammonium Formate Systems, p None
Original Measurements
Plyushchev, V. E.; Shklover, P. P.; Shkolnikova, L. M.; Kuznetsova, C. P.; Nadezhdina, G. V.; Dokl. Akad. Nauk SSR 160, 366-9 (1965).
Variables:
Room Temp: 25 - 50 °C
Prepared by:
St. Trendafilova, Chr. Balarew
Method/Apparatus/Procedure:
The isothermal method was used. The mixtures were stirred for one week. $\ce{La^{3+}$ and $\ce{Ce^{3+}$ were determined gravimetrically as $\ce{La2O3}$ and $\ce{Ce2O3}$, respectively. $\ce{Pr{3+}}$ was precipitated as $\ce{Pr2(C2O2)3}$ and the excess $\ce{H2C2O2}$ was back titrated with $\ce{KMnO4}$. 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. $\ce{La(OH)3}$ with formic acid. $\ce{Ce(CHO2).0.2H2O}$ was obtained by the reaction of $\ce{Ce2(CO3)3}$ with formic acid. $\ce{Pr(CHO2)3}$ was obtained by reacting freshly pptd. $\ce{Pr(OH)3}$ with formic acid. The $\ce{Pr2O3}$ had 0.05-1.5 mass% impurities. The formic acid has $n_{D}^{20}$ = 1.3712.
Estimated Errors:
Ambient temperature: The temperature was controlled to within ±0.1°C.
Components:
- Lanthanum formate, $\ce{ La(CHO2)3 }$; [2081-11-0] NIST WebBook
- Cerium formate, $\ce{ Ce(CHO2)3 }$; [3252-51-5] NIST WebBook
- Praseodymium formate, $\ce{ Pr(CHO2)3 }$; [3252-52-6] NIST WebBook
- Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
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(CHO2)3·nH2O 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.
Part 2. Solubility polytherm of the Ce(CHO2)3·0.2H2O-H2O system.
| $T$ (°C) | 100w1' | 100w1 | m1 (mol/kg) | m2 (mol/kg) | Phase (s) () |
|---|---|---|---|---|---|
| 25 | 0.20 | 0.34 | 6 x 10-3 | 0.012 | B |
| 40 | 0.19 | 0.32 | 6 x 10-3 | 0.012 | B |
| 50 | 0.19 | 0.32 | 6 x 10-3 | 0.012 | B |
(a) The solid phase is: A = La(CHO2)3.
(b) The molality values were calculated by the compilers.
(a) The solid phase is: B = Ce(CHO2)3·0.2H2O.
(b) The molality values were calculated by the compilers.
(a) The solid phase is: C = Pr(CHO2)3.
(b) The molality values were calculated by the compilers.
