Ammonothermal Synthesis and Crystal Structure of the Nitridoalumogermanate Ca1-xLixAl1-xGe1+xN3 (x approximate to 0.2)

Haeusler, Jonas; Eisenburger, Lucien; Oeckler, Oliver und Schnick, Wolfgang (2018): Ammonothermal Synthesis and Crystal Structure of the Nitridoalumogermanate Ca1-xLixAl1-xGe1+xN3 (x approximate to 0.2). In: European Journal of Inorganic Chemistry, Nr. 6: S. 759-764

Abstract

The new nitridoalumogermanate Ca1-xLixAl1-xGe1+xN3 (x approximate to 0.2) was synthesized from supercritical ammonia at 925 K and 185 MPa starting from the intermetallic precursor Ca3Al2Ge2 and Li as mineralizer. The crystal structure was refined by the Rietveld method;Ca1-xLixAl1-xGe1+xN3 with x approximate to 0.2 [a = 9.9822(5), b = 5.7763(2), c = 5.1484(1) angstrom, Z = 4, R-wp = 0.0492] crystallizes in orthorhombic space group Cmc2(1) (no. 36). Needle-shaped crystals with up to 15 mu m in length were detected by scanning electron microscopy. Possible cation ordering was analyzed by transmission electron microscopy. No superstructure reflections were observed in electron diffraction patterns and the structure model was confirmed by Z-contrast imaging. The composition was verified by energy-dispersive X-ray spectroscopy on single crystals and inductively coupled plasma optical emission spectrometry. Optical properties were studied by diffuse reflectance spectroscopy, showing a broad absorption band between 250 and 300 nm. The optical band gap was estimated to be 4.3 eV at room temperature using the Tauc method.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Chemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 1434-1948
• Sprache: Englisch