Structural and valence properties of the amorphous-metallic high-pressure phase of SnI/sub 4/

Journal Article · Sun May 15 00:00:00 EDT 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.37.8130· OSTI ID:5278600

Pasternak, M; Taylor, R D

Moessbauer spectroscopy (MS) in /sup 119/Sn and /sup 129/I was employed to investigate the evolution and properties of the high-pressure amorphous-metallic phase of SnI/sub 4/. Measurements were carried out at pressures up to 27 GPa using diamond-anvil cells. Both MS probes detect the onset of a new high-pressure phase at Papprox. =10 GPa. The relative abundance of the high-pressure phase increases with pressure, reaching 100% at Pgreater than or equal to20 GPa. Whereas the isomer shift delta/sub IS/(P) of Sn in the low-pressure phase has a positive slope, that of the high-pressure phase has a negative slope with an unusual plateau in the 15--20-GPa region. In the 0less than or equal toPless than or equal to10 GPa range the /sup 129/I MS reveals a single site. For Pgreater than or equal to10 GPa a spectral component evolves with pressure that coexists with the ''molecular'' phase and reaches an abundance saturation of approx. =50% at Pgreater than or equal to18 GPa. In contrast to the low-pressure phase this component shows a positive quadrupole coupling constant, whose magnitude is about half that of the low-pressure phase, a large eta value, and nearly identical delta/sub IS/ values. The high-pressure abundance determined by both /sup 119/Sn and /sup 129/I shows a dramatic pressure hysteresis. It is unequivocally determined that no SnI/sub 4/..-->..SnI/sub 2/+I/sub 2/ dissociation takes place. A model proposed for the high-pressure phase of SnI/sub 4/ consists of randomly oriented chains of SnI/sub 4/ tetrahedral molecules where two bridging iodines per molecule provide for the intermolecular association.

• Research Organization: Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 5278600
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 37:14
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
IODINE 129
MOESSBAUER EFFECT
TIN 119
VALENCE
TIN IODIDES
PHASE TRANSFORMATIONS
AMORPHOUS STATE
HYBRIDIZATION
HYSTERESIS
ISOMER SHIFT
METALS
MOLECULAR CRYSTALS
ORIENTATION
RANDOMNESS
VERY HIGH PRESSURE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CRYSTALS
DAYS LIVING RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
HALIDES
HALOGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODIDES
IODINE COMPOUNDS
IODINE ISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
RADIOISOTOPES
STABLE ISOTOPES
TIN COMPOUNDS
TIN HALIDES
TIN ISOTOPES
YEARS LIVING RADIOISOTOPES
360603* - Materials- Properties