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.

中文翻译：

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氮化铝锗酸盐 Ca1-x Li x Al1-x Ge1+x N3 (x ≈ 0.2) 的氨热合成和晶体结构

新的氮化铝锗酸盐 Ca1-xLixAl1-xGe1+xN3（x 近似于 0.2）是由超临界氨在 925 K 和 185 MPa 下合成的，起始于金属间化合物前体 Ca3Al2Ge2 和 Li 作为矿化剂。晶体结构通过 Rietveld 法精修；Ca1-xLixAl1-xGe1+xN3 与 x 近似为 0.2 [a = 9.9822(5), b = 5.7763(2), c = 5.1484(1) 埃, Z = 4, R -wp = 0.0492] 在正交空间群 Cmc2(1)（第 36 号）中结晶。通过扫描电子显微镜检测到长度可达 15 微米的针状晶体。通过透射电子显微镜分析可能的阳离子排序。在电子衍射图中没有观察到超结构反射，并且通过 Z 对比成像证实了结构模型。通过对单晶的能量色散 X 射线光谱和电感耦合等离子体光学发射光谱来验证该组合物。通过漫反射光谱研究了光学特性，显示了 250 到 300 nm 之间的宽吸收带。使用 Tauc 方法在室温下估计光学带隙为 4.3 eV。