Components:
(1) Dysprosium formate,
Dy(CHO2)3; [16920-26-6]
NIST WebBook
(2) Holmium formate,
Ho(CHO2)3; [3252-59-3]
NIST WebBook
(3) Water,
H2O; [7732-18-5]
NIST WebBook
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:
Ambient temperature: range of 25 - 50 °C
Prepared by:
St. Trendafilova, Chr. Balarew
Method/Apparatus/Procedure:
The isothermal method was used. The mixtures were stirred for one week. Dy3+ and Ho3+ were determined complexometrically. 1 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 Ho2O3 and Dy2O3 had 0.05-1.5 mass% and 2.3 mass% impurities, respectively. The formic acid has nD20 = 1.3712.
Estimated Errors:
Ambient temperature: The temperature was controlled to within ±0.1°C.
References
1 Martinenko, L. I.; Nauchn. Dokl. Vyssh. Shk. Khim. Khim. Tekhnol. N4, 718 (1958).
Experimental Values:
Note: 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·n H2O 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 1. Solubility polytherm of the Dy(CHO2)3-H2O system.
| T (°C) | 100w1' | 100w1 | m1 (mol/kg)a | m2 (mol/kg)a | Phase (s)b |
|---|---|---|---|---|---|
| 25.0 | 4.83 | 7.7 | 1.36 x 10-1 | 2.80 x 10-1 | A |
| 40.0 | 4.91 | 7.82 | 1.38 x 10-1 | 2.85 x 10-1 | A |
| 50.0 | 4.43 | 7.06 | 1.24 x 10-1 | 2.55 x 10-1 | A |
(a) These values were calculated by the compilers. (b) The solid phase is: A = Dy(CHO2)3.
Part 2. Solubility polytherm of the Ho(CHO2)3-H2O system.
| T (°C) | 100w1' | 100w1 | m1 (mol/kg)a | m2 (mol/kg)a | Phase (s)b |
|---|---|---|---|---|---|
| 25.0 | 10.39 | 16.5 | 3.07 x 10-1 | 6.59 x 10-1 | B |
| 40.0 | 11.52 | 18.29 | 3.45 x 10-1 | 7.46 x 10-1 | B |
| 50.0 | 8.2 | 13.02 | 2.36 x 10-1 | 4.99 x 10-1 | B |
(a) These values were calculated by the compilers. (b) The solid phase is: B = Ho(CHO2)3.
