Syntheses and Crystal Structures of Alkaline Earth Metal Hydrogen Acetylides AE(C2H)2 with AE = Ca, Sr, Ba
Year: 2024
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Crystalline Ba(C 2 H) 2 was obtained by the reaction of elemental barium dissolved in liquid ammonia, forming a blue electride, and acetylene (C 2 H 2 ) 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(C 2 H) 2 was solved and refined using synchrotron powder diffraction data. It crystallizes in the trigonal space group P 3̅ m 1 (no. 164) with Z = 1, all HC 2 – 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) 2 ) and CdI 2 -type structures. For Sr(C 2 H) 2, 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 2 – anions in these compounds. Similar results were obtained for Ca(C 2 H) 2, however this compound is almost completely amorphous. Upon heating Ba(C 2 H) 2 with additional elemental barium to 200 °C in vacuum, highly crystalline BaC 2 ( I 4/ mmm, Z = 2) was obtained.
Source: Inorganic Chemistry
Authors: Lisa Körtgen, Uwe Ruschewitz
Institution: University of Cologne
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funder: Deutsche Forschungsgemeinschaft
Award: G2987550605
OpenAlex ID: W4404889916