1. science
2. chemistry

Synthesis and Characterization of Lanthanide complexes with
1-hydroxy-2-naphthoic acid and Hydrazine as Ligands
Karuppannan Parimalagandhi, Sundararajan Vairam*
Department of Chemistry, Government College of Technology, Coimbatore 641013, India
*Correspondance should be addressed to S. Vairam; [email protected]
Six new lanthanide complexes [Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O, [where Ln =
La(III), Ce(III), Pr(III), Nd(III), Sm(III) and Gd(III)] of 1-hydroxy-2-naphthoic acid with
hydrazine as co-ligand, have been synthesized by the reaction of the corresponding metallic
nitrates with the 1-hydroxy-2-naphthoic acid and hydrazine in aqueous medium at pH 5. The
complexes are characterized by elemental analysis, IR, UV-Visible spectra, Magnetic
moment measurement, Simultaneous TG-DTA and Powder X-ray studies. IR spectra of the
complexes indicate that the ligands behave as bidentate ligand through COO-. The complexes
show the symmetric and asymmetric COO- in the range of 1410-1411 cm-1 and 1557-1559
cm-1 indicating bidental coordination. TG-DTA studies reveal that the compounds undergo
endothermic dehydration in the range of 98-110ºC followed by exothermic decomposition to
leave the respective metal oxides as the end product through oxalate intermediates. The SEMEDX studies reveal the presence of respective metal oxides in nanosize. X-ray powder
patterns show isomorphism among the complexes with similar molecular formulae.
1. Introduction
Hydroxy substituted aromatic carboxylic acids, when both -OH and –COOH in ortho
positions are important chelating agents in coordination chemistry. They form metal
complexes due to the existence of COO- ion held up by hydrogen bonding with hydroxy
hydrogen; even in aqueous solutions variety of complexes have been reported [1-3].
Furthermore, using this acid with organic bases, mixed ligand complexes have also been
prepared [4-6]. Hydrazine is the simplest diamine and has two donating sites due to which its
use as ligand leads to formation of polymeric complexes. In our laboratory we have been
synthesizing polymeric metal complexes using aromatic carboxylic acids [7-9] and organic
compounds of similar nature, such as squaric acid [10]. Owing to bridging ligation nature of
hydrazine and hydroxy aromatic carboxylic acids, we performed this work with an intention
of preparing polymeric lanthanide complexes containing 1-hydroxy-2-naphthoic acid and
hydrazine as ligands. In this paper, we have presented synthesis and characterization of
complexes by IR, UV, TG-DTA, SEM-EDX, powder XRD and magnetic measurements.
1
2. Experimental
All the chemicals used were of AR grade. The solvents are distilled prior to use, and double
distilled water is used for the preparation and chemical analysis. In all the reactions, 99.99%
pure hydrazine hydrate is used as received.
2.1. Preparation of Lanthanide complexes. Lanthanum oxide (0.325 g, 1 mmol) is dissolved
in a minimum quantity of 1:1 HNO3, evaporated to eliminate excess of acid, and dissolved in
20 mL of water. This is added slowly to freshly prepare aqueous solution (60 mL) of the
ligand containing 1-hydroxy-2-naphthoic acid (0.188 g, 1 mmol) and hydrazine (0.2 g, 4
mmol) stirring the reaction mixture at pH 5. Immediately turbidity developed which turned
out to be micro-crystalline solid. Then the complex is filtered, washed with water, alcohol
and then with ether and dried.
All other lanthanide complexes are prepared by similar procedure by adding the
respective metal nitrate solution to the ligand solution in the same molar ratio.
2.2. Physicochemical Techniques. The composition is fixed by chemical analysis. Hydrazine
content is determined by titrating against standard KIO3 (0.025 mol L-1) under Andrew’s
conditions [11]. The metals, after destroying the hydrazine and organic matter by treatment
with concentrated HNO3 and evaporating the excess HNO3 are determined volumetrically by
EDTA (0.01 mol L-1) using xylenol orange indicator [11].
IR spectra of the complexes in the region 4000-400 cm-1 were recorded as KBr pellets
using a Shimadzu FTIR-8201 (PC)S spectrophotometer. The compounds are insoluble in
water and organic solvents, and hence their electronic absorption spectra are recorded for
solid samples. Electronic absorption spectra of La(III), Pr(III), Nd(III), Gd(III), Sm(III) &
Ce(III) complexes are obtained using a Varian Cary 5000 recording spectrophotometer. The
magnetic susceptibility of the complexes was measured using a vibrating sample
magnetometer, Lakeshore VSM model 7410 at room temperature. The X-ray powder
diffraction patterns of the complexes were recorded using Bruker X-ray diffractometer
(model AXS D8 Advance) employing Cu-Kα radiation with nickel filter. The TG-DTA
experiments are carried out using Q600 SDT and Q20 DSC instrument, in air atmosphere at a
heating rate of 10ºC min-1 using 5 to 10 mg of the samples. Platinum cups are employed as
sample holders and alumina as reference. The temperature range is ambient to 800ºC. The
elemental analysis is carried out using an Elementar Vario ELIII CHNS elemental analyzer.
The SEM with EDX analysis was obtained using JEOL model JSM-6390 LV and JEOL
model JED -2300 instrument.
3. RESULTS AND DISSCUSION
3.1. IR Spectra. IR spectra of the complexes are shown in Figures (1-3) and important
assignments are given in Table. I & II. The presence of hydrazine in the complexes is
revealed from the absorption at 949-981 cm-1 corresponding to (N-N) stretching frequency,
which evidence the presence of bidentate bridging ligands [12, 13] and broad absorption
peaks in the range of 3550-3575 cm-1 is assigned to O-H vibrations of the associated water
2
molecules. An additional peak observed in the range 578-591 cm-1 is evidence for the
presence of lattice water in the complexes [14]. The COO- group coordinated to metal is
found by their symmetric (C=O) and asymmetric (C=O) vibration at 1410-1411 cm-1 and
1557-1559 cm-1 respectively. The difference between the above two ranges from 147-149 cm1
implies the bidental coordination [14] to metal. The vN-H stretching is observed in the range
of 3394 - 3421 cm-1. The other peaks are common with those of acid.
3.2. Electronic Spectra and Magnetic Susceptibility Measurements. The compounds are
insoluble in water and organic solvents, and hence their electronic spectra are recorded for
solid samples. The electronic spectra for Pr(III) and Nd(III) complexes shows absorptions at
22831, 21276, 20790, 17667, 16583 cm-1 and 19531, 18975, 15600, 14641, 13605, 12468
which are assigned to 3H4 → 3P2, 3P1, 3P0, 4G5/2, 1D2 and 4I9/2 → 4G9/2, 4G7/2, 2H11/2, 4F9/2, 4F7/2,
4
F5/2 transitions respectively [15, 16]. Magnetic moments from magnetic susceptibility
measurements for Pr(III) and Nd(III) are 3.40 BM and 3.55 BM respectively, are in good
agreement with the values reported [15].
3.3. Thermal analysis. TG-DTA of complexes are shown in Figures (4–7) and the thermal
data are given in Table-III. All the complexes undergo similar pattern of dehydration.
Initially all the water molecules are found to be lost showing endotherms in the range 98ºC to
110ºC. Since they undergo continuous decomposition after dehydration, showing broad
exotherms centered at (La-350ºC, Pr-300ºC, Nd-354ºC, Gd-392ºC, Sm-350ºC and Ce-395ºC),
the intermediates cannot be indentified clearly. However, stoichiometric calculation indicates
that the complexes undergo decomposition via the formation of respective oxalates. This fact
is substantiated by comparing [17-19] the decomposition temperatures of oxalate
intermediates with those reported in the literature. The final residues are found to be
respective oxides [17, 20-22] formed from the decomposition of oxalates showing exotherms
at (300ºC to 395ºC).
The oxides were further confirmed by their XRD patterns which are comparable with
the JCPDS data. While comparing the thermal behavior of similar type of complexes of the
same acid with transition metals, it is found that the hydrazine is not eliminated separately in
the case of lanthanide complexes. Hydrazine goes along with the decomposition of organic
moiety of the complexes. In the case of transition metal complexes, hydrazine is eliminated
separately showing clear exothermic peak in the range 260ºC to 300ºC [9]. This may be
because of the stability of the complexes lanthanides (hard acid) formed with hydrazine (hard
base). Further, the transition metal complexes have coordinated water molecules, whereas in
the case of lanthanide complexes water molecules are present in the lattice. Furthermore, the
final decomposition is found to happen in almost similar range of temperature viz. (La-710ºC,
Pr-720ºC, Nd-720ºC, Gd-740ºC, Sm-750ºC and Ce-710ºC). While the decomposition of
complexes is compared with of the pure acid, the complexes undergo decomposition at lower
temperature probably because of the fuelling nature of hydrazine and more carbon content of
the acid moiety. The Scheme of decomposition reactions are shown in (1).
The scheme of decomposition reactions are as follows:
3
[Ln(N2H4)4{C10H6(1-O)(2-COO)}1.5].3H2O
[Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5]
Ln2(C2O4)3 + 1.5O2
Pr2(C2O4)3 + 1.8O2
98-110 ºC
200-625ºC
600-800ºC
720ºC
[Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5] +3H2O
Ln2(C2O4)3
Ln2O3 + 6CO2
1/3Pr6O11 + 6CO2
(1)
where Ln = La (III),Ce(III),Pr(III),Nd(III),Sm (III) & Gd (III)
3.4. X- ray diffraction Analysis. The X-ray powder diffraction patterns of the complexes
[Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O,where Ln= La(III) and Nd(III) are given in figure
8 and 9 (representative examples). They show similarity among them, implying isomorphism.
3.5. SEM-EDX Studies. The complexes are calcined in muffle furnace at their decomposition
temperature, heating subsequently at the same temperature for one hour and analyzed for
their particle size, show that they are in nanoscale (39-42 nm). This fact is further
substantiated by their XRD patterns using Scherer’s formula [23] D = Kλ / βcosθ, where λ is
the X-ray wavelength, β is the full width of height maximum (FWHM) of a diffraction peak,
θ is the diffraction angle, and K is Scherer’s constant of the order of 0.89. The SEM – EDX
image of residue obtained from [Nd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O are shown in
figures (10,11) as representative examples. From their images, it is understood that the
residue is nanosized metal oxides with irregular shape.
4. Conclusion
1-hydroxy-2-naphthoic acid and hydrazine yields the complexes of formulae
[Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O,where Ln = La(III), Ce(III), Pr(III), Nd(III),
Sm(III) & Gd(III) at pH 5. Analytical data confirm their formulations. The hydrazine
complexes display an N-N stretching frequency in the range of 949-981 cm-1 showing
bidentate bridging nature in the complexes. The complexes undergo thermal decomposition
to metal oxide particles of nanosize. All the complexes decompose exothermally in the range
300ºC to 395ºC with elimination of corresponding oxalates. The magnetic and electronic data
indicate the presence of metal in the complexes. Powder XRD and SEM –EDX studies
confirm the formation of respective metal oxides.
References
[1]
[2]
T. Premkumar, and S. Govindrajan, “Divalent transition metal complexes of 3, 5pyrazoledicarboxylate,” Journal of Thermal Analysis and Calorimetry, vol.84, 395399, 2006.
E. Helen Pricilla Bai, and S. Vairam, “Spectral and Thermal Studies of Transition
Metal Complexes of Acetamido Benzoic Acids with Hydrazine,”Asian Journal of
4
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
Chemistry, vol. 25 no.1, 209-216, 2013.
T. Premkumar, and S. Govindrajan, “Transition metal complexes of pyrazine
carboxylic acids with neutral hydrazine as a ligand,” Journal of Thermal Analysis and
Calorimetry, vol.79, 115-121, 2005.
S. Yasodhai, and S. Govindarajan, “Coordination compounds of some divalent
metals with hydrazine and dicarboxylate bridges,” Synthesis and Reactivity in
Inorganic and Metal- Organic Chemistry, vol.30, no.4, pp.745–760, 2000.
K. Kuppusamy, and S. Govindrajan, “Synthesis, spectral and thermal studies of
some 3d- Metal hydroxybenzoate hydrazinate complexes,”Thermochimica Acta,
vol. 274, no.1- 2, pp.125-138, 1996.
Thathan Premkumar, and Subbiah Govindrajan, “Thermoanalytical and spectroscopic
studies on hydrazinium lighter lanthanide complexes of 2-pyrazinecarboxylic acid”
Journal of Thermal Analysis and Calorimetry, vol. 100, no. 2, pp. 725-732, 2010.
N. Arunadevi and S. Vairam, “3-hydroxy-2-naphthoate complexes of transition metals
with hydrazine-preparation, spectroscopic and thermal studies,” E-Journal of
Chemistry, vol. 6, supplement1, pp.S413–S421, 2009.
S. Devipriya, N. Arunadevi, and S. Vairam, “Synthesis and thermal Characterization
of Lanthanide(III) Complexes with Mercaptosuccinic Acid and Hydrazine as Ligands,
Journal of Chemistry. vol. (2013) 1-10 pages, 2013.
N. Arunadevi, S. Devipriya, and S. Vairam, “Hydrazinium metal 1-hydroxy-2naphthoates- new precursors for metal oxides,”International Journal of Engineering
Science and Technology. Vol.3, no. 1, pp. 1-8, 2009.
S. Vairam and S. Govindarajan, “Hydrazinium complexes of lanthanide and transition
metal squarates,” Polish Journal of Chemistry, vol.80, no.10, pp. 1601-1614, 2006.
A. I. Vogel, A Text Book of Quantitative Inorganic Analysis including Elementary
Analysis, The English Language Book Society and Longmans, Green Co, London,
UK, 3rd edition, 1975.
E. W. Schmidt, Hydrazine and its Derivatives- Preparation, Properties and Applications,
Wiley Interscience, New York, NY, USA, 1984.
S. H. Tarulli, O.V. Quinzani, J. Dristas, and E. J. Baran, “Thermal behaviour of copper (II)
complexes of haloaspirinates,” Journal of Thermal Analysis and Calorimetry, vol.60, no.2,
pp.505–515, 2000.
K. Nakamoto, Infrared and Raman spectra of Inorganic and Co-ordination
compounds, Wiley Interscience Co, New York, NY, USA, 6th edition, 2009.
W. T. Carnall, P. R. Fields, and K. Rajnak, “Electronic energy levels of the trivalent
lanthanide aquo ions. III. Tb3+,” The Journal of Chemical Physics, vol.49, no.10,
pp. 4412- 4423, 1968.
J. E. Huheey, E. A. Keiter, R. L. Keiter, O. K. Medhi et al., Inorganic ChemistryPrinciples of Structure and Reactivity, vol. 488, Dorling Kindersley, NewDelhi, India,
2007.
B. A. A. Balboul, A. M. Ei-Roud, E. Samir, and A. G. Othman, “ Non-isothermal
studies of the decomposition course of lanthanum oxalate decahydrate,”
Thermochimica acta 387 (2), pp. 109-114, 2002.
5
[18]
[19]
[20]
[21]
[22]
[23]
B. A. A. Balboul, and A. Y. Z. Myhoub, “The characterization of the formation
course of neodymium oxide from different precursors: A study of thermal
decomposition and combustion processes,” Journal of Analytical and Applied
Pyrolysis 89 (1), 95-101, 2010.
B. Raju and B. N. Sivasankar, “Spectral, thermal and X-ray studies on some new Bishydrazinelanthanide(III)glyoxylates,” Journal of Thermal Analysis and Calorimetry,
vol.94, no.1, pp. 289–296, 2008.
K. C. Patil, G. V. Chandrashekhar, and C. N. R. Rao, “Infrared spectra and thermal
decompositions of metalacetates and dicarboxylates,” Canadian Journal Chemistry,
vol. 46, pp. 257–265, 1968.
W. Brzyska, A. Krol, and M. Milanova, “Thermal decomposition of yttrium,
lanthanum and lanthanide benzene-1,3-dioxyacetates in an air atmosphere,”
Thermochimica Acta, 161, 95-103, 1990.
E. C. Rodrigues, A. B. Siqueira, E. Y. Ionashiro, G. Bannach and M. Ionashiro,
“Synthesis, Characterization and thermal behaviour of solid state compounds of 4methoxybenzoate with lanthanum (III) and trivalent lighter lanthanides,” Ecl. Quim,
Sao Paulo, 31(1), 21-30, 2006.
G. Cao, Nano structures and Nano Materials, Synthesis, Properties and Applications,
Imperial College Press, London, UK, 2004.
6
Table Captions
Table I. Analytical data of [Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O complexes
Table II. Characteristic I.R. bands of [Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O complexes
Table III. Thermal Analysis of [Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O complexes
7
Table I. Analytical data of [Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O complexes
Complexes
[La(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
[Pr(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
[Nd(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
[Gd(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
[Sm(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
[Ce(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
Colour
White
Light
Green
Light
Violet
Dull
White
Dull
White
Light
Yellow
Carbon
Found
(calc.)
Hydrogen
Found
(calc.)
Analytical data (%)
Nitrogen
Hydrazine
Found
Found
(calc.)
(calc.)
36.2 (36.4)
4.4 (4.0)
10.1 (10.4)
11.5 (11.6)
25.6 (25.7)
36.5 (36.3)
4.4 (4.1)
10.5 (10.4)
11.8 (11.9)
26.3 (26.2)
36.1 (36.2)
4.0 (4.1)
10.6 (10.5)
11.5 (11.7)
26.4 (26.3)
35.1 (35.3)
4.0 (3.9)
10.1 (10.2)
11.1 (11.3)
28.1 (28.2)
36.2 (36.3)
4.3 (4.1)
10.2 (10.3)
11.5 (11.6)
27.2 (27.4)
36.2 (36.3)
4.2 (4.3)
10.3 (10.2)
11.7 (11.8)
25.4 (25.5)
8
Metal
Found
(calc.)
Table II. IR data of [Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O complexes
υN-N
cm-1
υC=O
Asym
cm-1
υC=O
sym
cm-1
υC=O
asym-sym
cm-1
υOH
cm-1
[La(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
949
(m)
1441
(s)
141
[Pr(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
901
(m)
1582
(s)
1582
(s)
1442
(s)
[Nd(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
966
(m)
1557
(s)
[Gd(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
969
(m)
[Sm(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
980
(m)
[Ce(N2H4)2{C10H6
(1-O)(2-COO)}1.5].3H2O
966
1582
1438
144
(m)
(s)
(s)
(b): broad, (s):sharp, (m):medium
Molecular formula of
Complexes
υH2O
cm-1
υNH
cm-1
3407 (b)
591
(s)
3049
140
3420 (b)
583
(s)
3066
1444
(s)
113
3399 (b)
586
(s)
3049
1582
(s)
1442
(s)
140
3400 (b)
578
(s)
3066
1582
(s)
1442
(s)
140
3394 (b)
583
(s)
3049
3392 (b)
583
(s)
3033
9
Table III. Thermal data of [Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O complexes
Thermogravimetry
Temp.
Weight loss/ %
Range (°C) Obs.
Calc.
102(+)
65-228
10.2
10.1
[La(N2H4)2{C10H6
350(-)
228-600
48.9
49.0
(1-O)(2-COO)}1.5].3H2O
710(+)
600-800
66.8
67.0
99.5(+)
63-140
10.1
10.2
[Pr(N2H4)2{C10H6
350(-)
140-625
49.2
49.3
(1-O)(2-COO)}1.5].3H2O
720(+)
625-790
68.1
68.4
102 (+)
65-212
10.0
10.1
[Nd(N2H4)2{C10H6
360(-)
212-620
48.7
48.9
(1-O)(2-COO)}1.5].3H2O
720(+)
620-800
68.7
68.9
110 (+)
75-220
9.7
10.0
[Gd(N2H4)2{C10H6
390(-)
220-582
47.5
47.6
(1-O)(2-COO)}1.5].3H2O
740(+)
582-700
67.1
67.3
98.5(+)
67.8-200
10.1
9.8
[Sm(N2H4)2{C10H6
350(-)
200-480
44.0
43.8
(1-O)(2-COO)}1.5].3H2O
750(+)
480-700
64.0
63.6
125 (+)
75-200
10.3
10.2
[Ce(N2H4)2{C10H6
375(-)
200-500
49.3
49.1
(1-O)(2-COO)}1.5].3H2O
710(+)
500-625
67.9
67.6
(-) = Exotherm, (+) = Endotherm
Compound
DTA peak
Temp (°C)
10
Intermediate/End product
Dehydration
La2(C2O4)3
La2O3
Dehydration
Pr2(C2O4)3
Pr6O11
Dehydration
Nd2(C2O4)3
Nd2O3
Dehydration
Gd2(C2O4)3
Gd2O3
Dehydration
Sm2(C2O4)3
Sm2O3
Dehydration
Ce2(C2O4)3
CeO2
Figure Captions
Fig.1. IR spectrum of C10H6(1-OH)(2-COOH)
Fig.2. IR spectrum of [Gd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.3. IR spectrum of [Pr(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.4. TG-DTA spectrum of [La(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.5. TG-DTA spectrum [Pr(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.6. TG-DTA spectrum of [Nd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.7. TG-DTA spectrum of [Gd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.8. XRD pattern of [La(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.9. XRD pattern of [Nd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.10. SEM images of Nd2O3 obtained by [Nd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
residue
Fig.11. SEM-EDX image of Nd2O3
11
Fig.1. IR spectrum of C10H6(1-OH)(2-COOH)
Fig.2. IR spectrum of [Gd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
12
Fig.3. IR spectrum of [Pr(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.4. TG-DTA spectrum of [La(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
13
Fig.5. TG-DTA spectrum of [Pr(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.6. TG-DTA spectrum of [Nd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
14
Fig.7. TG-DTA spectrum of [Gd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
Fig.8. XRD pattern of [Ln(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O
15
Fig.9. XRD pattern of [Nd(N2H4)2{C10H6(1-O)(2-COO)1.5].3H2O
Fig.10. SEM images of Nd2O3 obtained by
[Nd(N2H4)2{C10H6(1-O)(2-COO)}1.5].3H2O residue
16
Fig.11. SEM-EDX image of Nd2O3
17