Hydrogen sites in A/sub 2/BH/sub y/ (A = Ca, Sr, Eu; B = Ir, Rh, Ru)

Journal Article · Fri Jun 01 00:00:00 EDT 1984 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(84)90235-4· OSTI ID:6683437

Westlake, D G

A geometric model has been applied to the A/sub 2/BH/sub y/ hydrides (deuterides), Eu/sub 2/IrD/sub 5/, Ca/sub 2/IrH/sub 5/, Sr/sub 2/IrD/sub 5/, Ca/sub 2/RhH/sub 5/, Sr/sub 2/RhH/sub 5/, Ca/sub 2/RuH/sub 6/ and Sr/sub 2/RuD/sub 6/, none of which can be synthesized directly by reaction of hydrogen (deuterium) gas with an A/sub 2/B compound. Hole radii and intersite distances were calculated for the two types of interstices in each compound. Ther are two very large cubical interstices per formula unit. These are coordinated by eight atoms of type A, but they must remain unoccupied in A/sub 2/BH/sub y/ with y = 5 (or 6), because of their proximity to the square pyramidal interstices, of which there are six per formula unit. The geometric model allows rationalization of the occupation of these pyramidal sites. Despite the very significant chemical differences between the compounds considered here and those for which the model was initially developed, the present results showed no inconsistency with geometric criteria requiring that occupied interstices in stable hydrides have minimum hole radii of 0.40 Angstrom and minimum hydrogen-hydrogen distances of 2.10 Angstrom. Published results indicate that the seemingly related compound Mg/sub 2/NiD/sub 4/ does not conform to these empirical rules, and this case is discussed.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 6683437
• Journal Information: J. Solid State Chem.; (United States), Vol. 53:1
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CALCIUM COMPOUNDS
CRYSTAL STRUCTURE
LATTICE PARAMETERS
STRUCTURAL MODELS
DEUTERIDES
EUROPIUM COMPOUNDS
HYDRIDES
IRIDIUM
RHODIUM COMPOUNDS
RUTHENIUM COMPOUNDS
STRONTIUM COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
DEUTERIUM COMPOUNDS
ELEMENTS
HYDROGEN COMPOUNDS
METALS
PLATINUM METALS
RARE EARTH COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties