Published 2004 | Version v1
Journal article Metadata-only

Order-disorder phase transition in NaBD4

Creators

  • 1. Lab. for Neutron Scattering, ETH Zurich and Paul Scherrer Inst., Villigen PSI (Switzerland)
  • 2. Physics Dept., Univ. of Fribourg, Perolles (Switzerland)

Description

By means of neutron diffraction the low-temperature crystal structure of NaBD4 has been determined. At 10 K the lattice parameters are a=4.332(1) Aa and c=5.869(1) Aa. Deuterium is found in a tetrahedral arrangement [sites (8g)] around B. The symmetry corresponds to space group P42/nmc. For room temperature the structure model for NaBD4 of Davis and Kennard with disordered deuterium distributed over two sites has been revised to space group Fm anti 3m. Thus the 190 K phase transition known from specific heat measurements is of order-disorder type, caused by reorientations of BD4 tetrahedra. (orig.)

Additional details

Publishing Information

Journal Title
Materials Science Forum
Journal Volume
443-444
Series
European powder diffraction. EPDIC 8
Journal Page Range
p. 287-290
ISSN
0255-5476
CODEN
MSFOEP

Conference

Title
8. European powder diffraction conference
Acronym
EPDIC-8
Dates
23-26 May 2002
Place
Uppsala (Sweden)

INIS

Country of Publication
Switzerland
Country of Input or Organization
Switzerland
INIS RN
35031136
Subject category
S36: MATERIALS SCIENCE;
Resource subtype / Literary indicator
Conference, Numerical Data
Descriptors DEI
CRYSTAL-PHASE TRANSFORMATIONS; DEUTERIUM COMPOUNDS; EXPERIMENTAL DATA; FCC LATTICES; LATTICE PARAMETERS; NEUTRON DIFFRACTION; ORDER-DISORDER TRANSFORMATIONS; SODIUM BORIDES; SPACE GROUPS; TEMPERATURE RANGE 0000-0013 K; TEMPERATURE RANGE 0273-0400 K; TETRAGONAL LATTICES
Descriptors DEC
ALKALI METAL COMPOUNDS; BORIDES; BORON COMPOUNDS; COHERENT SCATTERING; CRYSTAL LATTICES; CRYSTAL STRUCTURE; CUBIC LATTICES; DATA; DIFFRACTION; HYDROGEN COMPOUNDS; INFORMATION; NUMERICAL DATA; PHASE TRANSFORMATIONS; SCATTERING; SODIUM COMPOUNDS; SYMMETRY GROUPS; TEMPERATURE RANGE