| The phase equilibria solubility were studied for the ternary systems of Cs Br-REBr3-H2O(RE = La、Ce、Pr、Nd、Sm、Er、Tm) and the quaternary systems of Cs Br-REBr3-HBr-H2O(RE = Er、Tm) at 298.15 K using the isothermal solubility method, the corresponding phase diagrams were constructed. New solid-phase compounds Cs2REBr5·10H2O(RE = La、Ce、Pr、Nd、Sm)(2:1 type) were affirmed, while for the systems Cs Br + REBr3 + HBr+ H2O(RE = Er 、 Tm), solid phase compound Cs3Er2Br9·16H2O 、 Cs3Tm2Br9·16H2O(3:2 type) were confirmed. According to the phase diagrams, all of the seven new compounds were synthesized and obtained from the comlpicated systems, and characterized by X-ray power diffraction, thermal analysis method of TG-DTG, and fluorescence spectrum. The standard molar enthalpies of solution of the compounds in water were measured by microcalorimetry under the condition of infinite dilution and then their standard molar enthalpies of formation were determined. In this paper, the new compounds of Cs3Er2Br9·16H2O、Cs3Tm2Br9·16H2O were configured to be 100 m M pre-made solution, which will added to the culture media for the chlorella. The final concentration of the compounds are 10-1、10-2、10-3、 10-4、 10-5 m M, respectively. The growth state of Chlorella protothecoides and Chlorella pyrenoidosa in different culture media are observed, and the growth curve was plotted at last.The discoveries were showed as follows:1. The ternary systems of Cs Br-REBr3-H2O(RE = La、Ce、Pr、Nd、Sm、Er、Tm) and the quaternary systems of Cs Br-REBr3-HBr-H2O(RE = Er、Tm) at 298.15 K were investigated and the corresponding phase diagrams were established for the first time in the course of our present work.2. New conpounds of 2:1 and 3:1 types were obtained from the systems first time.3. Upconversion fluorescence phenomenon of new compounds obtained from the complicated systems was observed for the first time. For example, Cs2 Ce Br5·10H2O、Cs2Pr Br5·10H2O、Cs2Nd Br5·10H2O and Cs2 Sm Br5·10H2O show srong upconversion fluorescence at 524 nm(or 697 nm for Cs2 Ce Br5·10H2O) when excited at 785 nm. Such upconversion laser action at room temperature has numerous applications mainly in the fields of optical material of visible region excited in the near infrared region.4. The standard molar enthalpies of solution for the compounds of Cs2 La Br5·10H2O 、 Cs2 Ce Br5·10H2O 、 Cs2 Pr Br5·10H2O 、 Cs2 Nd Br5·10H2O 、 Cs2 Sm Br5·10H2O 、 Cs3Er2Br9·16H2O and Cs3Tm2Br9·16H2O were measured under the condition of infinite dilution, they are 49.61 k J·mol-1、50.83 k J·mol-1、52.49 k J·mol-1、49.64 k J·mol-1、50.17 k J·mol-1、- 6.69 k J·mol-1 and- 11.63 k J·mol-1 respectively. And their standard molar enthalpies of formation were calculated, as being-4739 k J·mol-1、- 4729 k J·mol-1、- 4739 k J·mol-1、- 4728 k J·mol-1、- 4724 k J·mol-1、- 7846 k J·mol-1 and- 7826 k J·mol-1, respectively.5. Reinforcing studies in Cs Br and REBr3 reaction in hydrochloric acid systematically by adding ternary systems Cs Br-REBr3-H2O(RE = La、Ce、Pr、Nd、Sm、Er、Tm), it makes us get results regularly. The research on the ternary systems of Cs Br-REBr3-H2O(RE = La、Ce、Pr、Nd、Sm、Er、Tm) and the quaternary systems Cs Br-REBr3-HBr-H2O(RE = Er、Tm) show that the phase chemistry behaviors are similar for the systems of La, Ce, Pr, Nd, Sm, and are different for the systems of Er, Tm. It is the “Bicomponent effect” of the rare earth element.6. The Chlorella protothecoides and Chlorella pyrenoidosa are used as subject algae species in our experiment. As a result, we found that the growth of Chlorella is restrained, when the concentration of Cs3Er2Br9·16H2O or Cs3Tm2Br9·16H2O is 10-1 m M and 10-2 m M. While the concentration of Cs3Er2Br9·16H2O or Cs3Tm2Br9·16H2O is in the rang of 10-3~10-5 m M, it makes a growth promoting effect on the Chlorella. |
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