EXPERIMENTAL DISCRIMINATION BETWEEN
BRIDGING AND NONBRIDGING OXYGEN PHOSPHORUS BONDS IN P2O5, Na2O GLASS BY
PULSED NEUTRON TOTAL SCATTERING
K. Suzuki, M. Ueno
To cite this version:
K. Suzuki, M. Ueno. EXPERIMENTAL DISCRIMINATION BETWEEN BRIDGING AND
NONBRIDGING OXYGEN - PHOSPHORUS BONDS IN P2O5, Na2O GLASS BY PULSED
NEUTRON TOTAL SCATTERING. Journal de Physique Colloques, 1985, 46 (C8), pp.C8261-C8-265. <10.1051/jphyscol:1985838>. <jpa-00225181>
HAL Id: jpa-00225181
https://hal.archives-ouvertes.fr/jpa-00225181
Submitted on 1 Jan 1985
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JOURNAL DE PHYSIQUE
Colloque C8, suppl6ment a u n012, Tome 46, d6cembre 1985
page C8-261
EXPERIMENTAL DISCRIMINATION BETWEEN B R I D G I N G AND N O N B R I D G I N G
OXYGEN
-
PHOSPHORUS BONDS I N P205,Na20 GLASS BY PULSED NEUTRON
TOTAL SCATTERING
K. Suzuki and M. Ueno
The Research I n s t i t u t e for Iron, SteeZ and Other Metals,
Tohoku University, Katahira 2-1-1, Sendai 980, Japan
R E S L J - Les liaisons oxygSne - phosphore p n t a n t e s e t non-pntantes dans des
verres p2 o5 - Na2 0 ont Bte differenciees 2 l ' a i d e de l a diffusion totale
de neutrons pulses fournis par une source 2 s p l 1 i a t i o n La loncpeur des liaisons
p u r l e s paires 0 - P non-pntantes e s t sensiblerent plus courte que pour l e s
paires p n t a n t e s , aussi bien dans l e s verres que dans l e c r i s t a l .
Abstract - Bridging and nonbridging oxygen-phosphorus bond. existing i n P2O5.
Na20 glass have been distinguished by the pulsed neutron t o t a l scattering
uslng a spallation neutron source. The bondlength f o r the nonbridging oxygen
-phosphorus pair is significantly shorter than t h a t for the bridging oxygenphosphorus pair in the glass a s well as in the crystalline counterpart.
The discrimination between the bridging and nonbridging oxygen atoms bound t o a cent r a l glass-forming cation in the plyhedral structure units constructing the three
~ s i o n a l n e t w o r kstructure i s one of the mst important keys for characterizing
the short-range structure of oxide glasses.
So f a r the measuranents of X-ray photoelectron s p e c t r o s ~
have
~ been carried out for
identifying the bridging (0°), nonbridging(0-) and free (0 ) oxygen atoms existing i n
Misawa etal/Z/have concluded from the high resos i l i c a t e and phosphate glasses/l/.
lution measurement of the radial distribution function t h a t Si-O- bondlength does
significantly shrink compared with Si-OObondlength i n Na20-2Si02 glass a s well a s in
Na2O.2SiO2 crystalline compound.
mere is a significant difference of the bondlength between bridging oxygen-phosphorus
i n NaP03 crystalbond (P-0°) and nonbridging oxygen-phosphorus bond (P-O- or/and MO)
Therefore it i s interesting to examine whether such a difference
l i n e cap3und/3,4/.
of the bondlength is s t i l l preserved o r not i n the counterpart of NaP03 glass.
In order to distinguish the P-OOand P-O-(or W O )bond on the radial distribution
function in r e a l space, we need t o extend the measureroent of the structure factor
SfQ) up t o an enontwusly high value of the scattering vector Q(=4.rrsinO/X) such a s
beyond 30 to 40 A-I. The tim-of-flight pulsed neutron total scattering e x p r h t
based on accelerator neutron sources offers a quite pawerful technigue, because a
relatively high flux of e p i t h e m l energy neutrons is easily supplied.
This study aims a t observing directly the separation of the bondlength and coordination n m k r between P-OOand P-Od(or WO)bond in P205-Na20 glass by the pulsed
neutron t o t a l scattering.
The glass sample
P205-Na20 glass was prepared by the same procedure done by Brady/5/.
was smashed into small pieces and then contained i n a vanadium m e t a l cylinder of 0.025
nun in w a l l thickness, 7.8 nun i n inner diameter and 70 mm i n length. The measurement
of S ( Q ) for the glass contained in the cylinder was made a t r o o m b n p r a t u r e using a
FO-F pulsed neutron t o t a l scattering spectrometer MARK I1 installed a t the Tohoku
University 300 E V electron LINAC/6/. During the rwasurement the glass sample con-
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1985838
JOURNAL DE PHYSIQUE
----0
10
20 Q(&')
I
I
30
40
Fig. 1 - Neutron total s t r u c t m factor S (Q) of P205*Na20glass.
Fig. 2 - Radial. distribution functions(RDF) of P 0 .Na 0 glass.
is truncated a t v x i o u s
oZ
form f r o m S(Q) m
vdds
&.
The Fourier trans-
JOURNAL DE PHYSIQUE
C8-263
tained i n the vanadium mtal cylinder c e l l was kept i n a vacuum chamber to prevent it
from hygroscapic reaction and also t o eliminate the background due t o air scattering
of incident neutrons. The procedures of data processing and analysis have been fully
described i n a previous pap2r/7/.
I11
-
RESULTS AND DISCUSSION
is
The exprirrental structure factor S (Q)of P205-Na20 glass rneasured up to Q = 40
shown i n Figure 1. The oscillatory behavior of the S ( Q ) is obviously found over the
a l l range of Q examined i n this study. Figure 2 shaws the radial distribution function(FDF) which i s defined as the Fourier transform of the S (Q) truncated a t various
values of
Here the RDF mans 4 ? r r 2 p g ( r ) . The f i r s t peak in the FDF is s p l i t
into two s&paks, when & value is extended beyond 35 A-1. The f i r s t subpak i s
nearlylccatedat r=1.50 A, while the position of the second subpeak is r=1.64 A.
It is not certain that these vdlues are f i n a l goals, because Figure 3 shows t h a t the
Qmax dependence of the s p l i t peak position is not saturated even a t &=
40 A-l.
I f the short-range structure of P205.Na20 glass i s assuroed to resemble t h a t of the
corresponding counterpart of NaP03 crystalline ampund such as l i s t e d i n Table 1,
the f i r s t and second subpeak can be surely assigned to the phosphorus-nonbridging
oxygen (P-O-) bond and phosphorus-bridging oxygen (P-OO)bond existing in the glass
res~ctively.
Based on the least-squared f i t t i n g using the gaussian functions, as shown in Figure
4, it is concluded t h a t the coordination nmkers of ncmbridging oxygen(0-) and
&.
-
-
Fig. 3 & dependence of the position
and area of the f i r s t peak in the RDF of
P205.Na 0 glass.
2
Fig. 4 The least-squared f i t t i n g
using the gaussian functions is applied
to the f i r s t peak profile of the RDF
for P205-Na20 glass.
JOURNAL DE PHYSIQUE
C8-264
Table 1 - Interatomic distances and coordination nmkers of 0 atoms bound to a P atom
in P-O bonds existing in NaP03 and P205 crystalline compounds and P205-Na20glass.
Nonbridging Oxygen
P-0-
B r i d g i n g Oxygen
o r P=OO bond
rp-O(A) np+O(atoms)
P-O0 bond
Ref.
rpeO
( A ) np+o (atoms)
Crystals
Glass
P205-Na20
1.50
2.1
1.64
2.0
T h i s work
Ar=0.05
(f0.1)
Ar=0.05
(20.1)
A r is the fluctuation width of the bondlength obtained by the l e a s t - ~ e d
f i t t i n g using the gaussian function.
Bridging
Fig. 5
-
[PO4] structure unit i n P205-Na20 glass.
+
bridging oxygen (Oo) atoms bound to a phosphorus atom are 2.1 and 2.0 0.1atoms in
P205-Na20 glass. merefore the basic structure-unit constructing P205.Na20 glass is
a distorted tetrahedron consisting of four 0 atoms, of which central hole is occupied
by a P atan. 'It.lo 0- atoms are connected to the central P atom with the P-O- bondlength of 1.50 A, while two O0 atoms are bound to the central P atom with the P-OO
bondlength of 1.64 A, a s sham i n Figure 5.
Table 1 indicates t h a t the both of P-O- and P-OObondlength in the glass a r e longer
than those i n the crystalline ampun&. Hawever the P-OObondlength is mre
extended than the P-O- bondlength. Such a behavior has been observed i n the case of
A small peak located around r = 3 . 0 A in the RDF corresponds
s i l i c a t e glasses, too/2/.
to the P-P correlation in P205-Na2O glass. Tnerefore we can find that an average
bondangle of w O - P i s about 130 O in P205.Na20 glass. I n contrast to s i l i c a t e
glasses, the Na+-O- correlation is not obviously distinguished f m the 0-0 correlation on the RDF of P205.Na20 glass. By subtracting the contribution of the 0-0
correlation from the second peak region, we can estimate t h a t the coordination n d r
= 1.5~2.0 atoms. This i s quite
of 0- atoms around a Na+ atom is approximately
different from that " ~ ~ + 4 atoms
% 5 has been often found i n Si02-Na20 glass.
?he authors would l i k e to thank Prof. M-Misawa f o r his kind discussion, and the
members of Nuclear Science Laboratory, Tohoku University f o r t h e i r operating the
electron LINAC and developing the computer program of data aquisition.
/1/ Anderson, R. P., "X-Ray Photmledron Spectrosaqy of Sodium S i l i c a t e Glass",
Amr. Chem. Soc. Weting, New York, 1973.
/2/Misawa, M., Price, D. L. and Suzuki, K., J. Non-Crystalline .Solids 37 (1980) 85.
/3/McAdam, A. , Jost, K. H. and Beagley, B., Acta Cryst., % (1968) 1 6 x .
/4/Jost, K. H., A c t a Csyst., 16 (1963) 640.
/5/Brady, G. W., J. Chem. ~ h y z ,28 (1958) 48.
/6/&no, M., Misawa, M. and ~ u z u k rK;., *s. Bp. Lab. Nucl. Sci., Tohoku University
13 (1980) 254.
n / ~ u z u k i , K., Misawa, M., K a i , K. and Watanabe, N., Nucl. Instrum. & ~ t h o d s
147 (1977) 519.
~ C r u i c k s h a n k ,D. W. J., A c t a Cryst.,
(1964) 677 and 679.
2