Research Article Synthesis, Crystal Structure and...

Hindawi Publishing CorporationJournal of CrystallographyVolume 2013 Article ID 146567 6 pageshttpdxdoiorg1011552013146567

Research ArticleSynthesis Crystal Structure and Electrical Properties ofthe Molybdenum Oxide Na192Mg204Mo3O12

Ennajeh Ines Mohamed Faouzi Zid and Ahmed Driss

Laboratoire deMateriaux et Cristallochimie Faculte des Sciences de Tunis Universite de Tunis ElManarManar II 2092 Tunis Tunisia

Correspondence should be addressed to Mohamed Faouzi Zid faouzizidfstrnutn

Received 28 May 2013 Accepted 4 August 2013

Academic Editors M Akkurt J Jasinski J-P Lang and D Sun

Copyright copy 2013 Ennajeh Ines et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

New molybdenum oxide Na192

Mg204

Mo3O12has been synthesized by the solid state method The title compound crystallizes in

the triclinic system (space group P-1)The unit cell parameters are a= 69660(7) A b= 86352(8) A c= 102501(8) A 120572= 106938(1)∘120573= 104825(1)∘ 120574= 103206(1)∘ V = 53872(9) A3 and Z = 2The compound is isotypical to Ag

2M2(MoO

4)3(M=Zn Mg Co Mn)

The structure can be described as a three-dimensional anionicmixed framework ofMoO4tetrahedra and pairs ofMg

2O10octahedra

sharing common edgesTheNa+ ions are disordered and located in the voids forming infinite channels running along the direction[100] The electrical conductivity investigated from 693K to 793K by AC impedance spectroscopy is low (301 times 10minus7 S cmminus1 at683K)

1 Introduction

The interest in the study of alkali molybdenum oxides isprimarily in the unique structural and physical propertiesof some of these compounds which include high anisotropictransport properties [1 2] and superconductivity and in theirimportant application in the field of energy and electronicsas described in several reviews [3 4] Some of complexmolybdates crystallize in structure types which show signif-icant ionic conductivity For example the structure of theNasicon type molybdate [5] is of great interest because ofhigh ionic conduction For this reason the characterizationof those oxides seems to be an important task In ourinvestigation we synthesize new crystal of molybdenumoxide Na

192Mg204

Mo3O12

In our bibliographical search we found the study of thephase diagram of the system Na

2MoO4-MgMoO

4[6] the

system contains a single intermediate compound Na2Mg5

(MoO4)6[7]The structural study reveals that the compound

is isotypical to Na2Mg5(MoO

4)6[7] Ag

2M2(MoO

4)3(M =

Co Mn Mg Zn) [8ndash10] and Na05Zn275

(MoO4)3[11]

(The cif file corresponding to the studied structure hasbeen deposited in the database of Karlsruhe Number CSD426651 (httpwwwfiz-karlsruhedeicsdhtml))

2 Experimental Details

21 Synthesis The compound is synthesized by the solid statemethod A stoichiometric mixture of NaCO

3(Fluka 71350)

(NH4)2Mo4O13(Fluka 69858) andMg(NO

3)2sdot6H2O (Fluka

63079) placed in a porcelain crucible is slowly annealedin air at 350∘C for 12 hours in order to eliminate volatileproducts The resulting mixtures were heated at 540∘C for7 days in air Then they were slowly cooled at 5∘Cday to490∘C and finally they were cooled at 50∘Cday to roomtemperature Single colorless crystals of double molybdateswere grown by spontaneous crystallizations from stoichio-metricmeltsThe compound is isotypical toNa

2Mg5(MoO

4)6

[4] and Ag2M2(MoO

4)3(M = Co Mn Mg Zn) [7ndash9] and

contains mixed frameworks of MoO4tetrahedra and pairs of

MgO6octahedra sharing common edges

22 X-Ray Data Collection Data collection was performedwith a CAD-4 Enraf-Nonius X-ray diffractometer [12] at298K with graphite monochromator using MoK

120572wave-

length An empirical psi-scan [13] absorption correctionwas applied The structure was solved and refined by full-matrix least squares based on 1198652 using SHELXS-97 andSHELXL-97 [14 15] respectively In the closest solution

2 Journal of Crystallography

O9

O2

Mg1

O7

NaMgO5

O4

Mo3

O1

Mo1

O3

O10

O11Na2

Mg2

O6

Mo2

O8 O7

O9

Na3

O5iiiO8iv

O12i

O11iv

O4viiiO12i

Figure 1 The asymmetric unit of Na192

Mg204

Mo3O12compound

(a) (b)

Figure 2 A view showing (a) Mg2Mo10O40and (b) Mg

2Mo8O32

proposed by the program only somemolybdenumatoms andmagnesium atoms were located Using SHELXL-97 programrefinements followed by Fourier differences were necessaryto find the positions of the other atoms remaining in thelattice yielding a good 119877 factor of 218 for all reflectionsand allowing the revolution of the positions of 12 peaks ofoxygen atoms on the difference Fourier map The structuregraphics were drawn with diamond 21 supplied by CrystalImpact [16] Crystal data and structure refinements details aresummarized in Table 1 The atomic coordinates and isotropicthermal factors are presented in Table 2 Table 3 contains themain interatomic distances in the coordination polyhedra ofthe studied structure

3 Results and Discussion

31 Structure Description The title compound is a newmem-ber of isostructural phases family includingNa

2Mg5(MoO

4)6

[7] Ag2M2(MoO


to Na05Zn275

(MoO4)3[11] The cell parameters of those

compounds are given in Table 4The asymmetric unit in Na

192Mg204

Mo3O12

compoundis shown in Figure 1 The structure is composed of two

octahedra Mg2O10

and three tetrahedra MoO4sharing cor-

ners and forming a cyclic group Mg2Mo3O19 The charge

compensation in the asymmetric unit is ensured by Na+cations

The structure may be represented as a three-dimensionalmixed framework of pairs of MgO

6octahedra sharing

common edges forming Mg2O10

group linked to MoO4

tetrahedra by corners Each two Mg2O10

octahedra sharingedges are surrounded either by ten tetrahedra formingMg(1)

2Mo10O40

group (Figure 2(a)) or by eight tetrahedraforming Mg(2)

2Mo8O32group (Figure 2(b))

The projection of the structure along [100] and [001]directions shows the presence of layers in the ac plane whichare connected by Mo(2)O

4polyhedra forming two types

of tunnels hexagonal along [100] direction (Figure 3) andsquared along [001] direction (Figure 4) The monovalentcations are located in tunnels forming infinite channels

The projection of a layer along the direction [010] showsthe presence of two types of Mg(1)

2Mo10O40

and Mg(2)2

Mo8O32chains connected by MoO

4tetrahedra (Figure 5)

In the crystal structure of Na192

Mg204

Mo3O12 the Mo

atom has a tetrahedral oxygen coordination with MondashOdistances varying within 1718(3)ndash1800(4) A with the average

Journal of Crystallography 3

b

c

MoMgNaMg

NaO

Figure 3 Projection of Na192

Mg204

Mo3O12

structure along [100]direction showing cavities where monovalent cations are located

MoMgNaMg

NaO

b

a


Mg204

Mo3O12

structure along [001]direction showing layers along a direction

of 1760 A close to the common values [14] Magnesiumcations occupy two crystallographically independent sitesMg1 and Mg2 which are located in an octahedral environ-ment with (119889 (Mg1ndashO) = 2056(3)ndash2167(3) A) and (119889 (Mg2ndashO = 1989(4)ndash2158(3) A) with the average of 2100 A

Sodium atoms occupy three different positions Na(1)Na(2) and the third site which is occupied by (Na+ Mg2+)The (Na1Mg11)ndashO bond lengths vary from 215 to 229 A(Table 3) In fact we remark that the short distance NandashO is

Table 1 Crystal data and structure refinement details for Na192Mg204Mo3O12

Empirical formula Na192Mg204Mo3O12

Formula weight (gmol) 57355Crystal system space group Triclinic P-1119886 (A) 69660(7)119887 (A) 86352(8)119888 (A) 102501(8)120572 (∘) 106938(1)120573 (∘) 104825(1)120574 (∘) 103206(1)119881 (A3) 53872(9)119885 2120583 (mmminus1) 369119863

119909(gsdotcmminus3) 3536119865(000) 535Crystal size (mm) 028 times 018 times 014

Crystal habit Colourless prism119879min119879max 0424406258Measured reflections 3666Independent reflections 2338Observed refl with 119868 gt 2120590(119868) 2211119877int 0021Datarestraintsparameters 23381184119877[119865

2gt 2120590(119865

2)] 0022

119908119877(119865

2) 0058

GooF = 119878 116Δ120588maxΔ120588min (esdotA

minus3) 078minus084

shorter than normal which indicates that the occupation ispartial with the M2+ atom

The (Na1Mg11)O5is surrounded by five oxygen atoms

(CN = 5) The voids between layers are occupied by sodiumatoms Na2 and Na3 are in the middle of concavities(Na1Mg11) lie on the extremity of the concavity attracted topolyhedra of two adjacent layers (Figure 4)

32 Electrical Measurements The electrical properties ofNa192

Mg204

Mo3O12

ceramic have been investigated usingcomplex impedance spectroscopy Impedance spectroscopymeasurements were carried out in a Hewlett-Packard 4192-Aautomatic bridge monitored by an HP microcomputer Theelectrical measurements are realized in the thermal range693ndash743K and frequency range of 5Hzndash13MHz Pellet wasprepared by isostatic pressing at 4 kbar and sintering at 480∘Cfor 2 h in air with 5Ksdotminminus1 heating and cooling rates Thethickness and surface of pellet were about 0159 cm and0807 cm2 having a geometric factor of 119890119878 = 0197 cmminus1Platinum electrodes were painted in the two faces of thepellet with a platinum paste to ensure good electric contactsThe Nyquist plots at different temperatures are shown inFigure 6 When temperature increases the radius of semi-circles decreases which indicates an activated conduction


Table 2 Atomic coordinates and isotropic thermal factors of Na192Mg204Mo3O12

Atom 119909 119910 119911 119880iso Occ (lt1)Mo1 01142(4) 00912(4) 03329(3) 00104(7)Mo2 07850(4) 03354(4) 07400(3) 00105(7)Mo3 05948(8) 02594(4) 01303(4) 00133(5)Mg1 00424(2) 02000(8) 00174(8) 00107(3)Mg2 06224(2) 00434(8) 03953(7) 00120(3)Na1 07123(3) 07072(2) 01966(2) 00219(6) 0917(9)Mg11 07123(3) 07072(2) 01966(2) 00219(6) 0042(8)Na2 04759(9) 05336(9) 05487(8) 00900(3) 050Na3 00340(2) 0507(2) 05199(9) 00290(2) 050O1 07258(7) 04739(5) 02418(5) 00544(9)O2 03473(5) 02349(4) 00075(3) 00198(6)O3 01729(6) 03074(4) 04221(4) 00283(7)O4 07536(5) 01913(4) 00362(3) 00221(7)O5 00790(4) 00561(3) 01472(3) 00124(5)O6 07797(5) 02956(4) 05600(3) 00177(6)O7 08334(5) 05524(4) 08268(3) 00229(7)O8 05351(5) 02240(4) 07349(3) 00184(6)O9 09802(4) 02684(4) 08377(3) 00178(6)O10 05657(6) 01487(6) 02471(4) 00363(9)O11 03273(4) 00301(4) 04206(3) 00132(5)O12 08781(5) 09886(4) 03507(3) 00184(6)

MoMgNaMg

NaO

a

c

Figure 5 Projection of chains structure along [001] direction show-ing layers along a direction

mechanism The intercepts of the semicircular arcs with thereal axis give an estimation of the resistance of materialWe have used the Zview software [17] to fit these curvesThe measured impedance can be modeled as an equivalentelectrical circuit composed of a resistor 119877 connected inparallel with a constant phase element CPE [18] By knowing

Table 3 Main interatomic distances (A) in Na192Mg204Mo3O12compound

Bond distances (A)Mo1ndashO3 1718(3)Mo1ndashO12i 1762(3)Mo1ndashO5 1780(3)Mo1ndashO11 1800(3)Mo2ndashO7 1732(3)Mo2ndashO6 1765(3)Mo2ndashO8 1766(3)Mo2ndashO9 1785(3)Mo3ndashO4 1736(3)Mo3ndashO1 1740(4)Mo3ndashO10 1758(3)Mo3ndashO2 1780(3)Mg1ndashO4vii 2056(3)Mg1ndashO9viii 2067(3)Mg1ndashO5 2076(3)Mg1ndashO7ii 2080(3)Mg1ndashO2 2109(3)Mg1ndashO5iii 2167(3)Mg2ndashO10 1989(4)Mg2ndashO12ix 2070(3)Mg2ndashO11 2119(3)Mg2ndashO11iv 2132(3)Mg2ndashO6 2148(3)Mg2ndashO8iv 2149(3)Na1ndashO8ii 2158(3)Na1ndashO1 2211(6)Na1ndashO9v 2232(3)Na1ndashO2vi 2250(3)Na1ndashO12 2298(4)Na2ndashO3 2279(8)Na2ndashO3ii 2411(9)Na2ndashO6ii 2780(3)Na2ndashO1ii 2859(9)Na3ndashO3 2272(18)Na3ndashO6ii 2371(19)Na3ndashO3x 2437(17)Na3ndashO6vii 2440(19)Na3ndashO1ii 2518(11)Na3ndashO1vii 2989(10)Symmetry codes i119909 minus 1 119910 minus 1 119911 ii minus 119909 + 1 minus119910 + 1 minus119911 + 1 iii minus 119909 minus119910 minus119911ivminus119909+ 1 minus119910 minus119911+ 1 v minus119909+ 1 minus119910+ 1 minus119911+ 1 vi minus119909+ 1 minus119910+ 1 minus119911 vii119909minus 1119910 119911 viii119909 minus 1 119910 119911 minus 1 ix119909 119910 minus 1 119911 x minus 119909 minus119910 + 1 minus119911 + 1

the value of resistance and the dimensions of the sample theconductivity has been calculated at each temperature

The variation of log (120590119879(SsdotKsdotcmminus1)) versus 1000T (Kminus1)is represented in Figure 7 The conductivity value at 683Kis 301 times 10minus7 S cmminus1 and the activation energy for Na+ions migration deduced from the slope is Ea = 137 eVNa192

Mg204

Mo3O12shows a low electric conductivity when


0 300000 600000 9000000

200000

400000

minusZ998400998400(ohm

)

Z998400 (ohm)

420∘C

430∘C

440∘C

(a)

0 150000 300000 4500000

40000

80000

120000

160000

200000

240000


)

Z998400 (ohm)

450∘C

460∘C

470∘C

(b)

Figure 6 Complex impedance spectra of Na192

Mg204

Mo3O12at various temperatures

Ln(120590T)

minus70

minus75

minus80

minus85

minus90

132 134 136 138 140 142 144 14610

4T

Ea = 137

Figure 7 Arrhenius plot of conductivity of Na192

Mg204

Mo3O12

ceramic

compared to those found for other molybdenum oxidecompounds (Table 5) [19 20]

4 Conclusion

Newmolybdate Na192

Mg204

Mo3O12is synthesized by a solid

state method The structure of our compound has beensolved by using X-ray diffraction The compound is formedby bioctahedra M

2O10

and MoO4tetrahedra connected via

common vertices The structure of this material has an openframework having different interconnecting tunnels runningalong [100] and [001] where the Na+ ions are located Theelectrical properties of the title compound are investigatedusing complex impedance spectroscopy The conductivityvalue at 683K is 301 times 10minus7 S cmminus1 and the activation energy

Table 4 Cell parameters of isotypical compounds

Compound Space group Cell parameters (A ∘)

Na2Mg5(MoO4)6 Triclinic P-1

10575(5) 8617(4) 6951(3)10342(4) 10267(4)11237(3)V = 53538 A3

Ag2Mg2(MoO4) Triclinic P-16978(1) 8715(2) 10294(2)10756(1) 10511(1) 10368(1)V = 54138 A3

Ag2Co2(MoO4) Triclinic P-16989(1) 8738(2) 10295(2)10767(2) 10528(2) 10387(2)V = 54179 A3

Ag2Zn2(MoO4) Triclinic P-16992(6) 8712(7) 10818(7)6424(2) 6651(2) 7627(3)V = 54266 A3

Na05Zn275(MoO4)3 Triclinic P-16983 8594 10825 658776619 7817V = 54181 A3

Table 5 Conductivity 120590 (Ssdotcmminus1) and conduction activation energy119864

119886(eV) of other compounds

Compound Temperaturerange (∘C) 119864

119886(eV) 120590 (Ssdotcmminus1)

Li3Cr(MoO4)3 200ndash400 106 26 times 10

minus6 (300∘C)Na5Sc(MoO4)3 mdash 072 6 times 10

minus6 (300∘C)Li2Mg2(MoO4)3 200ndash400 071 11 times 10

minus7 (300∘C)Na2In2Mo5O16 mdash 079 2 times 10



minus8 (300∘C)

for Na+ ions migration is Ea = 137 eV Na192

Mg204

Mo3O12

presents a low electric conductivity


References

[1] T Minami K Imazawa andM Tanaka ldquoFormation region andcharacterization of superionic conducting glasses in the systemsAgI-Ag

2O-M119909O119910rdquo Journal of Non-Crystalline Solids vol 42 no

1ndash3 pp 469ndash476 1980[2] A L Laskar and S Chandra Eds Superionic Solids and Solid

ElectrolytesmdashRecent Trends Academic Press San Diego CalifUSA 1989

[3] I Y Kotova and N M Kozhevnikova ldquoPhase relations in theNa2MoO4-MgMoO

4-Cr2(MoO

4)3systemrdquo InorganicMaterials

vol 34 no 10 pp 1068ndash1070 1998[4] I Y Kotova and N M Kozhevnikova ldquoPhase relations and

electrical properties of phases in systems Na2MoO4-AMoO

4-

R2(MoO

4)3(A =Mg Mn Co Ni R =Cr Fe)rdquo Russian Journal

of Applied Chemistry vol 76 no 10 pp 1572ndash1576 2003[5] N M Kozhevnikova ldquoSynthesis and study of the variable-

composition phase Na1minus119909

Co1minus119909

Fe1+119909

(MoO4)3 0 le 119909 le 04

with nasicon structurerdquo Russian Journal of Applied Chemistryvol 83 no 3 pp 384ndash389 2010

[6] V A Efremov V M Zhukovskii and Y G Petrosyan ldquoPhasediagram of the system Na

2MoO4-MgMoO

4rdquo Zhurnal Neor-

ganicheskoi Khimii vol 21 p 209 1976[7] R F Klevtsova V G Kim and P V Klevtsov ldquoAn X-ray

structural investigation of double molybdates Na2R5(MoO

4)6

where R =Mg Co Znrdquo Crystallography Reports vol 25 p 11481980 (Russian)

[8] GD Tsyrenova S F Solodovnikov E G Khaikina et al ldquoPhaseformation in the (Ag

2O)-(MgO)-(MoO

3) system and crystal

structure of new Ag2Mg2(MoO

4)3(M=Co Mn)rdquo Journal of

Solid State Chemistry vol 177 no 6 pp 2158ndash2167 2004[9] G D Tsyrenova S F Solodovnikov E G Khaikina and E

T Khobrakova ldquoPhase formation in the Ag2O-MgO-MoO

3

system and the crystal structure of new double molybdateAg2Mg2(MoO

4)3rdquo Russian Journal of Inorganic Chemistry vol

46 no 12 pp 1886ndash1891 2001[10] C Gicquel-Mayer M Mayer and G Perez ldquoEtude Structurale

duMolybdateDouble drsquoArgent et de ZincAg2Zn2Mo3O12rdquoActa

Crystallographica vol 37 pp 1035ndash1039 1981[11] C Gicquel-Mayer andM Mayer ldquoEtude Structurale duMolyb-

date Double Na05Zn275

(MoO4)3rdquo Revue De Chimie Minerale

vol 19 p 91 1982[12] A J M Duisenberg ldquoIndexing in single-crystal diffractometry

with an obstinate list of reflectionsrdquo Journal of Applied Crystal-lography vol 25 no 2 pp 92ndash96 1992

[13] A C T North D C Phillips and F S Mathews ldquoA semi-empirical method of absorption correctionrdquo Acta Crystallo-graphica vol 24 no 3 pp 351ndash359 1968

[14] G M Sheldrick ldquoA short history of SHELXrdquo Acta Crystallo-graphica A vol 64 no 1 pp 112ndash122 2007

[15] G M Sheldrick SHELXS-97mdashA Program for Crystal StructureDetermination University of Gottingen Gottingen Germany1997

[16] K Brandenburg and M Berndt Diamond Version 21 CrystalImpact Bonn Germany 2001

[17] D Johnson Zview Version 31c Scribner Associates 1990ndash2007[18] A K Jonscher ldquoThe interpretation of non-ideal dielectric

admittance and impedance diagramsrdquo Physica Status Solidi Avol 32 no 2 pp 665ndash676 1975

[19] L Sebastian Y Piffard AK Shukla F Taulelle and J Gopalakr-ishnan ldquoSynthesis structure and lithium-ion conductivity of

Li2minus2119909

Mg2+119909

(MoO4)3and Li

3M(MoO

4)3(M119868119868119868 =Cr Fe)rdquo Jour-

nal of Materials Chemistry vol 13 no 7 pp 1797ndash1802 2003[20] N I Sorokin ldquoIonic conductivity of double sodium-scandium

and cesium-zirconium molybdatesrdquo Physics of the Solid Statevol 51 no 6 pp 1128ndash1130 2009

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


O9

O2

Mg1

O7

NaMgO5

O4

Mo3

O1

Mo1

O3

O10

O11Na2

Mg2

O6

Mo2

O8 O7

O9

Na3

O5iiiO8iv

O12i

O11iv

O4viiiO12i

Figure 1 The asymmetric unit of Na192

Mg204

Mo3O12compound

(a) (b)

Figure 2 A view showing (a) Mg2Mo10O40and (b) Mg

2Mo8O32

proposed by the program only somemolybdenumatoms andmagnesium atoms were located Using SHELXL-97 programrefinements followed by Fourier differences were necessaryto find the positions of the other atoms remaining in thelattice yielding a good 119877 factor of 218 for all reflectionsand allowing the revolution of the positions of 12 peaks ofoxygen atoms on the difference Fourier map The structuregraphics were drawn with diamond 21 supplied by CrystalImpact [16] Crystal data and structure refinements details aresummarized in Table 1 The atomic coordinates and isotropicthermal factors are presented in Table 2 Table 3 contains themain interatomic distances in the coordination polyhedra ofthe studied structure

3 Results and Discussion

31 Structure Description The title compound is a newmem-ber of isostructural phases family includingNa

2Mg5(MoO

4)6

[7] Ag2M2(MoO


to Na05Zn275

(MoO4)3[11] The cell parameters of those

compounds are given in Table 4The asymmetric unit in Na

192Mg204

Mo3O12

compoundis shown in Figure 1 The structure is composed of two

octahedra Mg2O10

and three tetrahedra MoO4sharing cor-

ners and forming a cyclic group Mg2Mo3O19 The charge

compensation in the asymmetric unit is ensured by Na+cations

The structure may be represented as a three-dimensionalmixed framework of pairs of MgO

6octahedra sharing

common edges forming Mg2O10

group linked to MoO4

tetrahedra by corners Each two Mg2O10

octahedra sharingedges are surrounded either by ten tetrahedra formingMg(1)

2Mo10O40

group (Figure 2(a)) or by eight tetrahedraforming Mg(2)

2Mo8O32group (Figure 2(b))

The projection of the structure along [100] and [001]directions shows the presence of layers in the ac plane whichare connected by Mo(2)O

4polyhedra forming two types

of tunnels hexagonal along [100] direction (Figure 3) andsquared along [001] direction (Figure 4) The monovalentcations are located in tunnels forming infinite channels

The projection of a layer along the direction [010] showsthe presence of two types of Mg(1)

2Mo10O40

and Mg(2)2

Mo8O32chains connected by MoO

4tetrahedra (Figure 5)

In the crystal structure of Na192

Mg204

Mo3O12 the Mo

atom has a tetrahedral oxygen coordination with MondashOdistances varying within 1718(3)ndash1800(4) A with the average


b

c

MoMgNaMg

NaO


Mg204

Mo3O12


MoMgNaMg

NaO

b

a


Mg204

Mo3O12









2gt 2120590(119865

2)] 0022

119908119877(119865

2) 0058


minus3) 078minus084





Mg204

Mo3O12





MoMgNaMg

NaO

a

c







Mg204



0 300000 600000 9000000

200000

400000


)

Z998400 (ohm)

420∘C

430∘C

440∘C

(a)

0 150000 300000 4500000

40000

80000

120000

160000

200000

240000


)

Z998400 (ohm)

450∘C

460∘C

470∘C

(b)


Mg204


Ln(120590T)

minus70

minus75

minus80

minus85

minus90

132 134 136 138 140 142 144 14610

4T

Ea = 137


Mg204

Mo3O12

ceramic


4 Conclusion

Newmolybdate Na192

Mg204



2O10






10575(5) 8617(4) 6951(3)10342(4) 10267(4)11237(3)V = 53538 A3















minus8 (300∘C)


Mg204

Mo3O12



References






4-Cr2(MoO




4-

R2(MoO




Co1minus119909

Fe1+119909

(MoO4)3 0 le 119909 le 04



2MoO4-MgMoO




4)6



2O)-(MgO)-(MoO






3

















Li2minus2119909

Mg2+119909

(MoO4)3and Li

3M(MoO

4)3(M119868119868119868 =Cr Fe)rdquo Jour-










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




b

c

MoMgNaMg

NaO


Mg204

Mo3O12


MoMgNaMg

NaO

b

a


Mg204

Mo3O12









2gt 2120590(119865

2)] 0022

119908119877(119865

2) 0058


minus3) 078minus084





Mg204

Mo3O12





MoMgNaMg

NaO

a

c







Mg204



0 300000 600000 9000000

200000

400000


)

Z998400 (ohm)

420∘C

430∘C

440∘C

(a)

0 150000 300000 4500000

40000

80000

120000

160000

200000

240000


)

Z998400 (ohm)

450∘C

460∘C

470∘C

(b)


Mg204


Ln(120590T)

minus70

minus75

minus80

minus85

minus90

132 134 136 138 140 142 144 14610

4T

Ea = 137


Mg204

Mo3O12

ceramic


4 Conclusion

Newmolybdate Na192

Mg204



2O10






10575(5) 8617(4) 6951(3)10342(4) 10267(4)11237(3)V = 53538 A3















minus8 (300∘C)


Mg204

Mo3O12



References






4-Cr2(MoO




4-

R2(MoO




Co1minus119909

Fe1+119909

(MoO4)3 0 le 119909 le 04



2MoO4-MgMoO




4)6



2O)-(MgO)-(MoO






3

















Li2minus2119909

Mg2+119909

(MoO4)3and Li

3M(MoO

4)3(M119868119868119868 =Cr Fe)rdquo Jour-










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






MoMgNaMg

NaO

a

c







Mg204



0 300000 600000 9000000

200000

400000


)

Z998400 (ohm)

420∘C

430∘C

440∘C

(a)

0 150000 300000 4500000

40000

80000

120000

160000

200000

240000


)

Z998400 (ohm)

450∘C

460∘C

470∘C

(b)


Mg204


Ln(120590T)

minus70

minus75

minus80

minus85

minus90

132 134 136 138 140 142 144 14610

4T

Ea = 137


Mg204

Mo3O12

ceramic


4 Conclusion

Newmolybdate Na192

Mg204



2O10






10575(5) 8617(4) 6951(3)10342(4) 10267(4)11237(3)V = 53538 A3















minus8 (300∘C)


Mg204

Mo3O12



References






4-Cr2(MoO




4-

R2(MoO




Co1minus119909

Fe1+119909

(MoO4)3 0 le 119909 le 04



2MoO4-MgMoO




4)6



2O)-(MgO)-(MoO






3

















Li2minus2119909

Mg2+119909

(MoO4)3and Li

3M(MoO

4)3(M119868119868119868 =Cr Fe)rdquo Jour-










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0 300000 600000 9000000

200000

400000


)

Z998400 (ohm)

420∘C

430∘C

440∘C

(a)

0 150000 300000 4500000

40000

80000

120000

160000

200000

240000


)

Z998400 (ohm)

450∘C

460∘C

470∘C

(b)


Mg204


Ln(120590T)

minus70

minus75

minus80

minus85

minus90

132 134 136 138 140 142 144 14610

4T

Ea = 137


Mg204

Mo3O12

ceramic


4 Conclusion

Newmolybdate Na192

Mg204



2O10






10575(5) 8617(4) 6951(3)10342(4) 10267(4)11237(3)V = 53538 A3















minus8 (300∘C)


Mg204

Mo3O12



References






4-Cr2(MoO




4-

R2(MoO




Co1minus119909

Fe1+119909

(MoO4)3 0 le 119909 le 04



2MoO4-MgMoO




4)6



2O)-(MgO)-(MoO






3

















Li2minus2119909

Mg2+119909

(MoO4)3and Li

3M(MoO

4)3(M119868119868119868 =Cr Fe)rdquo Jour-










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




References






4-Cr2(MoO




4-

R2(MoO




Co1minus119909

Fe1+119909

(MoO4)3 0 le 119909 le 04



2MoO4-MgMoO




4)6



2O)-(MgO)-(MoO






3

















Li2minus2119909

Mg2+119909

(MoO4)3and Li

3M(MoO

4)3(M119868119868119868 =Cr Fe)rdquo Jour-










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



Research Article Synthesis, Crystal Structure and...

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