Temperature dependence of repeat distance of tin fluoride-graphite intercalation compound and the two-dimensional phase transition

Cl0

134

TEMPERATURE

DEPENDENCE

INTERCALATION

Fujio

OKINO’

Department

and

The

temperature

second-stage

fluorine K.

’

A

between

160

splitting.

data

lQF-NMR been

barely

TRANSITION

and Technology

140

K a suggest

At room

of

temperature,

a

of the

as the temperature

is lowered

to 173

temperature

172 -

At

a rapid

spectra

exchange

results. occurs

doublet

“QSn-M&sbauer

measured.

in the

similar

and

suggesting

broadens

drastically

results

Science

lQF-NMR,

broadening

K and

These

for

show

sizable

of

previously

peak

broadens

‘1Sn-M6ssbauer

observed.

have

The

FLUORIDE-GRAPHITE

PHASE

386, Japan

is observed

ligands.

of Textile

dependences

peak

It, however,

Faculty

Ueda

CxSnFy

sharp

OF TIN

TOUHARA

of Chemistry,

Ilniversity,

DISTANCE

AND THE TWO-DIMENSIONAL

Hidekazu

Shinshu

single

OF REPEAT

COMPOUND

range

room

with

temperature

decreasing

appears

owing

a two-dimensional

The

a singlet

temperature,

to a

phase

133 K.

strong

is and

quadrupole

transition

of the guest

species. In order

to shed

temperature were

prepared

gas

being

the

using

range

results

ranges

show

in

contraction,

in

guest

species.

143-298

K,

123-143 thickness

expansion, occurs

is

of AHF was

the

The samples with

fluorine

measured

was in

K. of

highly

DSC measurements

that It

the

it

in

the

guest

those

spectra.

The

the two-dimensional

speculative,

are in progress.

an ice-water

ca.

to

species.

the

with

is raised

contracts

corresponds

unexpected,

accord

with

as the temperature

but

’ ‘aSn-Mi%sbauer

to be associated Though

reflection

( = 1.9 8) increases

range

and

measured

CxSnFy.

solution

(006)

and

apparent

‘OF-NMR

SnFa-saturated of

we have

of stage-2

dooo

the

of

phenomenon,

distance

K.

the

is likely

be the case.

in an

in

contraction

therefore, the

K

instead

this

changes

that

on the

repeat

d-spacing

of 298-78

discontinuously

which

The

78-123

&contraction

of the HOPG

bubbled.

temperature The

some more light

dependence

a

of

the

observed phase

ca.

the

range

peak

S

0.05

Although

temperature

in

0.01

at

feature

contraction, transition

like transition

of

might