Phase transformation and crystal structure of La2Ni 7Hx studied by in situ X-ray diffraction

Kenji Iwase, Kouji Sakaki, Yumiko Nakamura, Etsuo Akiba

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

The phase transformation of La2Ni7 during hydrogenation was investigated by in situ X-ray diffraction. We found two hydride phases, La2Ni7H7.1 (phase I) and La2Ni7H10.8 (phase II), during the first absorption cycle. The metal sublattice of phase I was orthorhombic (space group Pbcn) with lattice parameters a = 0.50128(6) nm, b = 0.8702(1) nm, and c = 3.0377(1) nm. The sublattice for phase II was monoclinic (space group C2/c) with lattice parameters a = 0.51641(9) nm, b = 0.8960(1) nm, c = 3.1289(1) nm, and β = 90.17(1)°. The lattice parameter c increased with the hydrogen content, while a and b decreased in the formation of phase I from the alloy. Phase transformation from phase I to phase II was accompanied by isotropic expansion. The La2Ni4 and LaNi5 subunit expanded by 48.9% and 6.0% in volume, respectively, during hydrogenation to phase I. They expanded an additional 14% and 5.8%, respectively, in the formation of phase II. The obtained volume expansion suggested different hydrogen distribution in the La2Ni4 and LaNi5 subunit during hydrogenation.

Original languageEnglish
Pages (from-to)8763-8768
Number of pages6
JournalInorganic Chemistry
Volume49
Issue number19
DOIs
Publication statusPublished - Oct 4 2010

Fingerprint

Hydrogenation
hydrogenation
Lattice constants
phase transformations
lattice parameters
Crystal structure
Phase transitions
X ray diffraction
sublattices
crystal structure
Hydrogen
diffraction
x rays
expansion
hydrogen
Hydrides
hydrides
Metals
cycles
metals

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

Phase transformation and crystal structure of La2Ni 7Hx studied by in situ X-ray diffraction. / Iwase, Kenji; Sakaki, Kouji; Nakamura, Yumiko; Akiba, Etsuo.

In: Inorganic Chemistry, Vol. 49, No. 19, 04.10.2010, p. 8763-8768.

Research output: Contribution to journalArticle

Iwase, Kenji ; Sakaki, Kouji ; Nakamura, Yumiko ; Akiba, Etsuo. / Phase transformation and crystal structure of La2Ni 7Hx studied by in situ X-ray diffraction. In: Inorganic Chemistry. 2010 ; Vol. 49, No. 19. pp. 8763-8768.
@article{f844169ac7f44c8cbb8957c1dbb93be9,
title = "Phase transformation and crystal structure of La2Ni 7Hx studied by in situ X-ray diffraction",
abstract = "The phase transformation of La2Ni7 during hydrogenation was investigated by in situ X-ray diffraction. We found two hydride phases, La2Ni7H7.1 (phase I) and La2Ni7H10.8 (phase II), during the first absorption cycle. The metal sublattice of phase I was orthorhombic (space group Pbcn) with lattice parameters a = 0.50128(6) nm, b = 0.8702(1) nm, and c = 3.0377(1) nm. The sublattice for phase II was monoclinic (space group C2/c) with lattice parameters a = 0.51641(9) nm, b = 0.8960(1) nm, c = 3.1289(1) nm, and β = 90.17(1)°. The lattice parameter c increased with the hydrogen content, while a and b decreased in the formation of phase I from the alloy. Phase transformation from phase I to phase II was accompanied by isotropic expansion. The La2Ni4 and LaNi5 subunit expanded by 48.9{\%} and 6.0{\%} in volume, respectively, during hydrogenation to phase I. They expanded an additional 14{\%} and 5.8{\%}, respectively, in the formation of phase II. The obtained volume expansion suggested different hydrogen distribution in the La2Ni4 and LaNi5 subunit during hydrogenation.",
author = "Kenji Iwase and Kouji Sakaki and Yumiko Nakamura and Etsuo Akiba",
year = "2010",
month = "10",
day = "4",
doi = "10.1021/ic100964j",
language = "English",
volume = "49",
pages = "8763--8768",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "19",

}

TY - JOUR

T1 - Phase transformation and crystal structure of La2Ni 7Hx studied by in situ X-ray diffraction

AU - Iwase, Kenji

AU - Sakaki, Kouji

AU - Nakamura, Yumiko

AU - Akiba, Etsuo

PY - 2010/10/4

Y1 - 2010/10/4

N2 - The phase transformation of La2Ni7 during hydrogenation was investigated by in situ X-ray diffraction. We found two hydride phases, La2Ni7H7.1 (phase I) and La2Ni7H10.8 (phase II), during the first absorption cycle. The metal sublattice of phase I was orthorhombic (space group Pbcn) with lattice parameters a = 0.50128(6) nm, b = 0.8702(1) nm, and c = 3.0377(1) nm. The sublattice for phase II was monoclinic (space group C2/c) with lattice parameters a = 0.51641(9) nm, b = 0.8960(1) nm, c = 3.1289(1) nm, and β = 90.17(1)°. The lattice parameter c increased with the hydrogen content, while a and b decreased in the formation of phase I from the alloy. Phase transformation from phase I to phase II was accompanied by isotropic expansion. The La2Ni4 and LaNi5 subunit expanded by 48.9% and 6.0% in volume, respectively, during hydrogenation to phase I. They expanded an additional 14% and 5.8%, respectively, in the formation of phase II. The obtained volume expansion suggested different hydrogen distribution in the La2Ni4 and LaNi5 subunit during hydrogenation.

AB - The phase transformation of La2Ni7 during hydrogenation was investigated by in situ X-ray diffraction. We found two hydride phases, La2Ni7H7.1 (phase I) and La2Ni7H10.8 (phase II), during the first absorption cycle. The metal sublattice of phase I was orthorhombic (space group Pbcn) with lattice parameters a = 0.50128(6) nm, b = 0.8702(1) nm, and c = 3.0377(1) nm. The sublattice for phase II was monoclinic (space group C2/c) with lattice parameters a = 0.51641(9) nm, b = 0.8960(1) nm, c = 3.1289(1) nm, and β = 90.17(1)°. The lattice parameter c increased with the hydrogen content, while a and b decreased in the formation of phase I from the alloy. Phase transformation from phase I to phase II was accompanied by isotropic expansion. The La2Ni4 and LaNi5 subunit expanded by 48.9% and 6.0% in volume, respectively, during hydrogenation to phase I. They expanded an additional 14% and 5.8%, respectively, in the formation of phase II. The obtained volume expansion suggested different hydrogen distribution in the La2Ni4 and LaNi5 subunit during hydrogenation.

UR - http://www.scopus.com/inward/record.url?scp=77957287740&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77957287740&partnerID=8YFLogxK

U2 - 10.1021/ic100964j

DO - 10.1021/ic100964j

M3 - Article

C2 - 20812739

AN - SCOPUS:77957287740

VL - 49

SP - 8763

EP - 8768

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 19

ER -