| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
This research have been done to obtain and promote the knowledge on the structure and bond in the Zintl compounds, the intermetallic compounds between the alkali or alkaline earth metals and posttransition elements, and the related compounds such as Zintl anions by means of Mossbauer spectroscopy. To perform this purpose, several attempts have been carried out ; the preparation of Zintl compound and synthesis of Zintl anion by a electrochemical method were carried out.
After the many reviews of the reaction condition, the Zintl compounds have been prepared by the crystallization from the melt containing the stoichiometric amount of the alkali metal and antimony in an aluminum crucible under the nitrogen atmosphere. The binary compound K_3Sb, KSb, KSb_2, Na_3Sb, NaSb and Mg_3Sb_2 were prepared by this method. The binary intermetallic compound between antimony and the transition elements were prepared by the crystallization from the melt in a evacuated quartz tube. The attempt to prepare the Zintl anion by electrochemical method has been failed in spite of much effort.
The ^<121>Sb Mossbauer spectra for the intermetallic compounds have been measured at 20K.The spectra for the compounds of M-Sb system (M = Na, K) shows that M_3Sb and Mg_3Sb_2 are an ionic compounds consist of the M^+ and Sb^<3-> ions, the same electron configuration as that of Xe. For MSb and KSb_2, on the other hand, much covalent interactions between antimony atoms are suggested and the excess electrons are mainly held in the Sb 5p orbitals. The order of the number of the accepted electrons are increased in the order MSb_2 <MSb <M_3Sb, indicating the ionic character of these compounds. The Mossbauer spectra for Cu_3Sb, Cu_2Sb, Ag_3Sb, AuSb_2, and ZnSb suggest the covalent nature for these compounds.
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