Körtgen Lisa, Ruschewitz Uwe
Department of Chemistry and Biochemistry, Institute for Inorganic and Materials Chemistry, University of Cologne, Cologne 50939, Germany.
Inorg Chem. 2024 Dec 16;63(50):23749-23756. doi: 10.1021/acs.inorgchem.4c03869. Epub 2024 Dec 1.
Crystalline Ba(CH) was obtained by the reaction of elemental barium dissolved in liquid ammonia, forming a blue electride, and acetylene (CH) injected into the reaction vial with the electride solution. From the colorless precipitate that was obtained after evaporation of the ammonia, the crystal structure of Ba(CH) was solved and refined using synchrotron powder diffraction data. It crystallizes in the trigonal space group 3̅1 (no. 164) with = 1, all HC anions are aligned along [001]. It is the first crystal structure of an alkaline earth metal hydrogen acetylide published up to now, showing a close similarity with the brucite (Mg(OH)) and CdI-type structures. For Sr(CH), a product with a significantly reduced crystallinity was obtained, but its powder diffraction pattern makes an isotypic crystal structure very likely. IR/Raman spectroscopic investigations as well as GC analysis of the gases released upon hydrolysis unambiguously confirm the existence of HC anions in these compounds. Similar results were obtained for Ca(CH), however this compound is almost completely amorphous. Upon heating Ba(CH) with additional elemental barium to 200 °C in vacuum, highly crystalline BaC (4/, = 2) was obtained.
通过将溶解在液氨中的单质钡反应形成蓝色电子化物，并将乙炔（CH）注入装有电子化物溶液的反应瓶中，得到了晶体Ba(CH)。从氨蒸发后得到的无色沉淀中，利用同步辐射粉末衍射数据解析并精修了Ba(CH)的晶体结构。它结晶于三方空间群3̅1（编号164），a = 1，所有HC阴离子沿[001]方向排列。它是迄今为止发表的碱土金属氢乙炔化物的首个晶体结构，与水镁石（Mg(OH)）和CdI型结构有密切相似性。对于Sr(CH)，得到了结晶度显著降低的产物，但其粉末衍射图谱表明很可能具有同型晶体结构。红外/拉曼光谱研究以及水解时释放气体的气相色谱分析明确证实了这些化合物中存在HC阴离子。对于Ca(CH)也得到了类似结果，然而该化合物几乎完全非晶态。在真空中将Ba(CH)与额外的单质钡加热至200°C，得到了高结晶度的BaC（4/，a = 2）。
