Universität zu Köln

Kleinöder, Tim ORCID: 0009-0004-7757-9978, Hoverath, Carolin ORCID: 0009-0005-7835-1075, Lorenz, Thomas ORCID: 0000-0003-4832-5157, Wiethölter, Joshua ORCID: 0009-0006-8470-2764, Block, Theresa, Pöttgen, Rainer, Förster, Tom, Suta, Markus ORCID: 0000-0001-8024-6665 and Ruschewitz, Uwe ORCID: 0000-0002-6511-6894 (2026). Eu2Li(C3)H: A Carbide Hydride Phase Incorporating Eu2+. Journal of the American Chemical Society, 148 (3). pp. 3525-3537. ACS American Chemical Society. ISSN 0002-7863

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Abstract

Reactions between carbon and lithium hydride in a mixed metal europium/lithium flux led to the synthesis of Eu2Li­(C3)­H. At room temperature, the compound crystallizes in the tetragonal space group P4/mbm (no. 127, Z = 2; Ca2Li­(C3)H type) and undergoes a second-order structural phase transition below ∼250 K to an orthorhombic low-temperature modification (no. 55, Pbam; Z = 4), crystallizing in a new structure type. The phase transition was monitored by using single-crystal X-ray diffraction (SCXRD) and temperature-dependent high-resolution powder diffraction data. Infrared (IR) spectroscopy and gaschromatographic analysis (GC) of the hydrolysis products confirm the existence of a first europium compound with an allylenide anion (C34–). Magnetic susceptibility measurements and 151Eu Mössbauer spectroscopy reveal the presence of divalent europium, suggesting a charge-balanced carbide hydride (Eu2+)2(Li+)­(C34–)­(H–). A transition to a (soft) ferromagnetic ground state is observed below 42 K. In situ high-pressure, high-temperature (HPHT) investigations indicate a surprisingly high stability of Eu2Li­(C3)H and yield a bulk modulus K0 = 65 GPa. Quantum chemical calculations (DFT + U) reveal a pseudogap at the Fermi level and allow the classification as a rare-earth metal Zintl phase exhibiting both ionic and covalent bonding contributions.

Item Type:	Article
Creators:	Creators Email ORCID ORCID Put Code Kleinöder, Tim UNSPECIFIED https://orcid.org/0009-0004-7757-9978 UNSPECIFIED Hoverath, Carolin UNSPECIFIED https://orcid.org/0009-0005-7835-1075 UNSPECIFIED Lorenz, Thomas UNSPECIFIED https://orcid.org/0000-0003-4832-5157 UNSPECIFIED Wiethölter, Joshua UNSPECIFIED https://orcid.org/0009-0006-8470-2764 UNSPECIFIED Block, Theresa UNSPECIFIED UNSPECIFIED UNSPECIFIED Pöttgen, Rainer UNSPECIFIED UNSPECIFIED UNSPECIFIED Förster, Tom UNSPECIFIED UNSPECIFIED UNSPECIFIED Suta, Markus UNSPECIFIED https://orcid.org/0000-0001-8024-6665 UNSPECIFIED Ruschewitz, Uwe UNSPECIFIED https://orcid.org/0000-0002-6511-6894 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-812297
Identification Number:	10.1021/jacs.5c19173
Journal or Publication Title:	Journal of the American Chemical Society
Volume:	148
Number:	3
Page Range:	pp. 3525-3537
Number of Pages:	13
Date:	28 January 2026
Publisher:	ACS American Chemical Society
ISSN:	0002-7863
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Inorganic Chemistry
Subjects:	Chemistry and allied sciences
['eprint_fieldname_oa_funders' not defined]:	Publikationsfonds UzK
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/81229