Structural characterization of Mg3CrH∼6—a new high-pressure phase synthesized in a multi-anvil cell at 8 GPa

Autor:	Tetsuo Sakai, Daisuke Kyoi, Helen Blomqvist, Dag Noréus, Ewa Rönnebro
Rok vydání:	2004
Předmět:	Hydride Mechanical Engineering Metals and Alloys chemistry.chemical_element Crystal structure Crystallinity Hydrogen storage Chromium Crystallography chemistry Mechanics of Materials X-ray crystallography Materials Chemistry Orthorhombic crystal system Magnesium ion
Zdroj:	Journal of Alloys and Compounds. 368:279-282
ISSN:	0925-8388
DOI:	10.1016/j.jallcom.2003.05.002
Popis:	With modern X-ray diffraction refinement methods it was possible to identify the first phase in the Mg–Cr–H system, Mg 3 CrH ∼6 from minute sample volume in spite of poor crystallinity and coexisting impurity phases. The new hydride was synthesized at 8 GPa in a high-pressure multi-anvil cell at 873 K. An orthorhombic unit cell was found with a =9.635(2) A, b =8.615(2) A, c =4.8040(7) A, space group Pnam (no. 62), Z =4, V =398.77 A 3 . Chromium is surrounded by a distorted cube of magnesium atoms with average Cr–Mg distances of 2.9(1) A. The hydrogen positions were not possible to determine, as only a small sample amount could be prepared. If the metal atom structure is compared to already known metal hydrides it can be concluded that Mg 3 CrH ∼6 consists of chromium hydrido complexes counterbalanced by magnesium ions. A high hydrogen content was confirmed with thermal desorption spectroscopy.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::f08b99a1976d6245bfc2223e771ac513 https://doi.org/10.1016/j.jallcom.2003.05.002 Zobrazit plný text záznamu Full Text from ScienceDirect