| Autor: |
Reckeweg, Olaf, DiSalvo, Francis J., Dinnebier, Robert E., Funk, Christian, Schleid, Thomas |
| Zdroj: |
Zeitschrift für Naturforschung B; April 2024, Vol. 79 Issue: 4 p271-281, 11p |
| Abstrakt: |
Cesium dicyanamide Cs[C2N3] (≡ Cs[N(CN)2] or Cs[dca]) was obtained by a metathesis reaction in form of transparent colorless platelets. The results of single-crystal X-ray structure measurements and refinements (C2/c, Z= 8) with the monoclinic cell parameters a= 932.31(8), b= 1274.67(9), c= 824.94(7) pm, β= 110.803(3)° at −70 °C and a= 939.59(7), b= 1281.58(8), c= 827.57(6) pm, β= 110.610(3)° at 20 °C corroborate earlier results for this compound. The Raman and IR spectra of Cs[C2N3] are presented for the first time and the result compares well with those of NaCs2[C2N3]3. The heat-driven cyclotrimerization process of Cs[C2N3] was studied by thermal analyses (DSC) and temperature-dependent X-ray powder diffraction methods. At 370 °C, its trimerization product Cs3[C6N9] is formed, crystallizing in the orthorhombic space group Pbamwith the cell parameters a= 3043.0(3), b= 1052.4(1) and c= 415.21(4) pm for Z= 4. The IR spectrum of this cesium tricyanomelaminate (Cs3[C6N9] or Cs3[TCM]) is presented, but a well-resolved Raman spectrum could not be acquired owing to fluorescence phenomena. An overview about the cyclotrimerization reactions of all pseudo-binary alkali-metal dicyanamides (A[C2N3]) to their corresponding tricyanomelaminates (A3[C6N9]) with A= Li–Cs gives a basis for a discussion of the different thermal and structural characteristics. |
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Supplemental Index |
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