Diffusion and clustering in the Cd1−xBixF2+x solid solution : a fluorine NMR study

P108

358

DIFFUSION

AND CLUSTERING

A FLUORINE

NMR

Suh Kyung-Soo, Laboratoire 351 tours

de Chimie

du Solide

conductors

high mobility

CdF2

matrix,

substitute

SOLID SOLUTION

cdl-xBixFZ+x

J.M.Reau

J.Senegas,

du CNRS,Universite

F- ion

e.g. Cd l_xM'xF2+x

Cedex

have been

, where

de Bordeaux

a trivalent

is

Cl1 . two cations

that involves solid solution cdl--xBixF2+x electrical of high polarizability has very good

the association fluorite

structure,

proposed

from

increases

of 2:2:2

of 2 vacancies

clusters

in the normal

variation

properties.

constituted

positions

2 F' and 2 F" interstitial

the linear

anions

of log u and

AE,

has been when

in the composition range (0.05 \< x < 0.35). 19 by F NMR of the Cdl_xBixF2+x

has

sublattices

shown

re. The motions of diffusive The NMR

above

of the mobile

study

has allowed

of clusters with

x # 0.05

fluoride

at rising

F- ions above

solid

temperatu-

T # 350 K

are

may result

mainly

J.M.Reau .

of

type in Cdl_xBixF2+x x of the electrical conductivity

l- M-El Omari,

(1990)

the hypothesis

of 2:2:2

increasing

and consequently

415

them

to justify

2:2:2 clusters

121

of different

between

x

nature.

the formation Improvement

the existence

exchanges

and

by

of the

The investigation solution

the

with

The

in Cdl xBixF2+x

involving

and

prepared

H'

I,

(France)

structure

of CaF2-type

of the

( M' = In,La,Ce,Nd,Gd,Er,Bil

The existence

:

and P.Hagenmuller

33405 Talence

de la Liberation,

New ionic a

IN THE

STUDY

from

from

and J.S&egas,

the

higher

number

that of the mobile

Phys.

Stat.

of

anions.

Sol.(a)

,