American Mineralogist, Volume 62, pages 819-823, 1977

X-ray study of KuLiFeznSr'Cl,a djerfisheriteJike compoundr

BnNleltIN S. TINI

Chemical Engineering D iuision, A rgonne N ational Laboratory A rgonne,I llinois604 39

Abstract

The X-ray powder diffraction pattern ol a djerfisherite-like compound, KuLiFeroSz"Cl, recovered as one of the reaction products in a battery development program at Argonne National Laboratory, is similar to that of the mineral which occurs in meteoritesand in terrestrialvein deposits.A structure of this compound, proposed on the basisof the X-ray data, was refinedto an R of 0.06 using38 FeKa/Mn reflectiondata. The cell is cubic,probable spacegroup is Pm3m and a : 10.358+ 0.005 A. The structure has clustersof eight edge- shared FeSn tetrahedra about the face-centersof the cube similar to that in ' Potassium.chlorine, and lithium atoms are distributed among theseclusters.

Introduction that chlorine was indeed presentand not as a con- taminant, A researchprogram is in progressat Argonne Na- The first terrestrial occurrence of djerfisherite' tional Laboratory to develop rechargeablebatteries KaCur(Fe,Ni),'S,owith a = 10.41A, was reported by for electrical-vehiclepropulsion and for load-leveling Genkin et al. (1969). Dobrovol'skaya et al. (1975) applications(Nelson et al., 1974).The electrochemi- have recognizedthree typesof djerfisherite:(1) where cal cells for these batteries have a molten-salt elec- iron is predominant (meteorites,skarns), (2) copper- trolyte of LiCl-KCl eutecticand operate at temper- containing(alkaline rocks), and (3) nickel-containing atures of 400-450'C. In one type, the negative (kimberlites).Compositional data for some djerfish- electrodeis a Li-Al alloy, and the positiveelectrode is erite-type compounds found in various media are FeS. Severalnew phaseshave beenfound in the posi- summarizedin Table l. tive electrodes(Martin et al.,1974 Mrazek and Bat- tles, 1975).One phaseis a compound which givesan Experimental X-ray powder diffraction pattern that is similar to The electrochemicalpreparation of a djerfisherite- that of the mineral djerfisherite. Wet-chemical analy- type compond will be describedby Mrazek and Bat- sis of this compound, extracted from an electrode,2 tles (in preparation).A. E. Martin (1975) has de- led to the formula, Ku ul-io.Fe2o.oS2u.rClr.o.It is cubic, scribed the out-of-cell preparation of this phase. It primitive, with a : 10.358+ 0.005 A. Djerfisherite, was produced by the reaction of LizFeS, with Fe in observedin two meteorites(Fuchs, 1966),was ana- molten LiCl-KCl eutectic (58.2 mole percent lyzed as K3(Na,Cu)(Fe,Ni),rS,n,with two formula LiCl-41.8 mole percent KCI) at 400-450'C. The X- units per unit cell and with a : 10.34+ 0.01 A. Fuchs ray powder diffraction patterns of the out-of-cell observedone weight percentchlorine, but the Com- preparations have a : 10.360+ 0.005 A' and they missionon New Minerals of the International Miner- appearthe sameas that of the electrochemicallypro- alogical Association recommendedthat chlorine be duced material. excluded from this formula. El Goresy et al. (1968, Crystallographic data for the electrochemically 1971) have supported Fuchs' original observation prepared phase were obtained using the Norelco powder camera of 114.6 mm diameter, and filtered 'This auspicesof the U. S. work was performed under the FeKa radiation. Unit-cell parameterswere derivedby Energy Researchand DevelopmentAdministration. extrapolation of qnnt uJ. cos20, after correction for '2The details are reported by Mrazek and Battles (in prepara- X-ray film intensities tion), Argonne National Laboratory. Mr. K. J. Jensen,Analytical film shrinkage. Thirty-eight Chemistry Laboratory, performed the chemicalanalysrs. were recordedwith a Leedsand Northrup densitome- 819 820 TANI: DJERFISHERITE-LIKE COMPOUN D

Table l. Compositionsof djerfisheritetype compounds ferred to the point positionsof spacegroup Pm3m. This model, with the formula, K.LiFernS2.Cl,was Source Fomula* alsoin reasonableagreement with the chemicalanal- ysis, Kr.ulio.uFernoSru.rClr.o. The atom positionsfor Pena Blanca Spring ( achondrite) (t"2 ) this structurewere used as a startingpoint in least- "2. r"to. 3 l. 1Ni0.3coo.6 za. otze. z91r, r- K6. (Ft22 l .gNto,6cto. s) z4, oSz5. ttrt. 2- squaresrefinement. After adjustmentof the scalefac- tor, the least-squareson coordinatesand temperature St. Marks (enstatlte chondrite) K6 (F"2t.9Nio factors convergedin four cyclesto R : 0.06 using . 3Nto,4 . rc"1 .4) 24 . osz4 .6c11 . o- K5 (F"2 unit weights.The final coordinatesare presentedin ,4Nto.3 2.tNio . :ctt.6) 24.osr, .ucro. ,** given Toluca (iron neteorite) Table3. The interatomicdistances are in Table K6 (Ftzt. . z SNlt, 8tuo.4) 24. otz5 .5clt. l' 4. Table 5 showsthe calculatedand observedX-ray Talnakh (ore deposlt) powder pattern intensities.There is good overall Ka. (Ftr7.9Nlo. 8 6cts. s)zt. osza.o- agreementwhich indicates the correctness of the pro- Khlbiny (mssif pegnarites) posedmodel. *r.0""0. (u"rr. ) i"tr. , ,t'o ., ro.oaru. r** Althoughthe refinementwas made in spacegroup ElectrochenLcal cell *** Ks Pm3m,either space group P43m or P432is alsopos- ,sLlo.6F"2a. osz5. 9crt. o sible.Further refinementin spacegroups of lower xuomposltiong are referenced to the trangltion atofr symmetry(and consequentincrease in parameters) ratio of 24.0. +81 coresy et a1, (1968), electron nicro-probe analysis. did not seemjustified because of the low R-factor **Fuchs (1966), electron micro-probe analysis. +fcenkin et al. (1969), nlcro-x-ray spectrographic alreadyobtained, the reasonablebond distancesfor analysis. +*sokolova (197I), this model,and the limited numberof measuredre- eb- al. shsalqal analysis; chlorine present, about 1.4 weLghr percent, Dmltrieva and Ilyukin (1975). flections.Figure I showsthe forwardhalf of the unit ***Mrazek and Bactlea (.1n preparatlon), wet cheDical analysLs. cell of KrliFeroS2"Cl. Discussion ter and convertedto integratedvalues. Weak in- The structurehas 24 distortedtetrahedra. Each tensitydata werecollected after longer exposure, and sharesthree edgeswith other tetrahedraforming a then scaledand collatedwith the primary reflection clusterof eight tetrahedraabout the face-centersof data. On a scaleof 0 to 100, ll reflectionswere the cube.The clusteris linked to other clustersby greaterthan [4, and 9 reflectionsrecorded 0. An corner-sharingof a tetrahedron. absorptioncorrection was appliedusing pR : 1.5, The compound, BaFezS3(Hong and Steinfink, for a samplein a 0.1 mm O.D. capillary. 1972),also has a structurein which a tetrahedron Least-squaresrefinement on coordinates,scale fac- sharesthree edges with neighboringtetrahedra. How- tor, and thermal parameterswas performedwith a ever, theseare pairs of tetrahedralinked by edge- modificationof the programof Businget al. (1962), sharingto other pairs forming an infinitechain of - Theprogram minimizes the function >llF,l' lF"ff tetrahedra.Pentlandite, (Fe,Ni)rS. (Lindqvist et al., and permitsrefinement on overlappedX-ray powder 1936;Hall and Stewart,1973), not only has three diffractiondata. The final refinementwas carried out in spacegroup Pm3m, using atomic scattering factors for Fe2+,K1+, S2-, Clt- and Lil+ from the Inter- Table 2. Crystallographic data for K.LiFq.S,.Cl national Tables for Crystallography (1962). Dis- persioncorrections were appliedto all atoms except System Cubl-c lithium (Cromer, 1965).The basiccrystallographic dataare shownin Table2. Space Groupo Pn3n, P43n or P432 unit cell (A) 10.3s8 I .Oos I Structuredetermination vorurne (f3) 1111.3 In viewof the lack of sufficientdata, trial structures Molecul-e/ce11 I for the electrochemicalphase were established Formula Vileight 2450.99 by DensLty g/cnJ (calculated) 3.66 * modeling.Derived structures were based on thepack- (measured) 3.7 ing of FeSotetrahedra. Of thevarious trial structures, the one basedon the superstructureof sphaleriteled *Mrazek and Battles (in preparation). to reasonabledistances. and the atomscould be re- TANI: DJERFISHERITE-LIKE COMPOU ND 821

Table 3 K.LiFe.S*Cl, point positions,positional coordinates Table 5. X-ray powder diffraction data for K"LiFeaSzuCl* and isotropictemperature factors*

N K.L d(ca1c)A d(obs)i 1(calc)** r(obs) Atom

100 10.358 10.36 40.3 45,O Fe 24m 0 . 3683(8) 0 . 3683(8) 0. 1310(8)1.6 110 7.324 t.J4 28.8 32.0 s(1) I2h 0.247(2) 0. 500 0.0 r.0 111 5.980 s.99 44.O 45.0 s(2) 8g 0.226 (z) o.226(2) 0.226(2) 1.0 0.1 0.0 s(3) 6f o.2sL<2) 0. 500 0.500 L.7 200 5.r79 4.633 0.0 0.0 K 6e 0.29 6(2) 0.0 0.0 L.) 2ro Li 1b 0. 500 0. 500 0. 500 1t c1 la 0. 000 0. 000 0. 000 1' 2Ir 4.229 0.1 0.0 220 3.662 0.4 0.0 3O0,22r 3.453 3.452 8.8 10.0 *Estimated standard errors indi.cated in parenthesis 3.276 3.275 11 a 27.0 in terms of last significant figures. 310 311 3.L23 3.726 37.2 ?q n

222 2.990 2.990 tz.o 75.0 320 2.873 2.876 6.6 7.4 edge-sharingtetrahedra, but also has a cluster of 32L 2.768 2.769 2.L 2.O 1.0 0.0 eight tetrahedra about the face-centersof the unit 400 2.590 4L0,322 2.5L2 2.5r2 t_l.4 L2.0 cell. The metal-to-metalarray forms a primitive cube 2.52 A on edge.This is on the order of the metal-to- 330,411 2.442 2.438 2.8 3.0 331 4t.J 4).U metal separationin pure iron. In K.LiFe2oSruCl,the 2.376 2.376 420 2.316 2.3L5 to 3. t iron-to-iron separation forms a near cube which is 42L 2.260 2.267 1.0 about 2.71 on edge. The compound, K.LiFer4Sr6Cl, 332 2.208 2.205 1.6 can be derived from pentlandite by the appropriate 422 2.LL5 0.3 0.0 removal and replacement of atoms other than the 430,500 2.072 2.07r 10.8 10.0 common cluster of tetrahedra.Genkin et al. (1969) 510,431 2.032 2.O3r ).b 6.0 interpeted the presenceof relict pentlandite in Tal- 511,333 L.994 r.992 13.2 l_3.0 520,432 r.924 1.923 qn 5.5 nakh djerfisherite as an indication of djerfisherite genesisby replacementof pentlandite. 527 1.891 0.8 0.0 Potassium,chlorine, and lithium occupy sites be- 440 1.831 r..831 100.0 100.0 447,522 l-.803 1.802 4,4 4.9 tween the tetrahedral clusters.Potassium is bonded 530,433 L.776 r.775 8.4 6. t 531 L.757 L.75L Q' 6.J

,A ')\ 600,422 r.726 I.IZO Table 4 Selectedinteratomic distances and anglesin 610 1.703 0.0 0.0 KuLiFezrSzuCl* 6rr,532 1.680 r.679 1.1 u.) 620 1.638 0.0 0.0 62L,540, 1 ^.tA to Dis tances Distances 443 1.619 2.9 1.598 2.7 2.7 Fe-S(1) 2.30(1) x2 Fe-Fe 2.7r(2) 54L r.598 .fJJ 2.4 2.5 Fe-S ( 2) 2.30(2) Fe-tre 2.73(2) x2 1.580 t.579 Fe-S(3) 2. 30(1) ozz t.562 1.561 L7.4 17.0

K-s( 1) 3.32(2) x4 c1-K 3.07(2) x6 K-s ( 2) 3.39(2) x4 r.l-s ( 3) 2.58<2) x6 *RelatLve intensities. FeKl filtered radiatlon. **Absorptlon corrected pR = 1.5.

Atoms

S(1) -Fe-s ( 1) 107.5(5) to eight sulfurs and to one chlorine, resulting in an -Fe-s s ( 3) (t) 107.0(s) x2 averagevalue of K-S : 3.36 A and K-Cl : 3.07 A. s (2)-I'e-s (1) 106.4(7)x2 s (2)-Ie-s (3) 121.9(8) Although the K-S distance appears reasonablefor this coordination, the K-Cl value may be somewhat *D1"t.o""" in I and angles l-n degrees, with low. Lithium is surroundedby an octahedralarray of standard errors Lndlcated 1n parentheses in tems distance of 2.58 A is also of last significant figures, sulfur atoms. The Li-S reasonablefor this coordination. 822 TANI. DJERFISHERITE.LIKE COMPOUN D

would have to dependon further analyses,especially electricaland magnetic measurements.

Acknowledgments The writer is indebted to Dr. Stanley Siegel for helpful dis- cussions,to Mr. Myron I. Homa and Dr. Paul T Cunningham of the Analytical Chemistry Laboratory and to Dr. Robert K Steu- nenberg of the Battery Program for their support, and to Mr. Louis H. Fuchs for supplying information on djerfisherite com- pounds. References Busing, W. R., L. O. Martin and H. A. Levy (1962) ORFLS, a Fortran crystallographicleast-squares refinement program. U. S Natl. Tech. Inf. Seru., ORNL-TM-305. Cromer, D. T ( 1965)Anomalous dispersioncorrections computed from self-consistentfi eld relativistic Dirac-Slater wave functions. Acta Crystallogr., 18, 17-23. Dmitrieva, M. T. ( 1976)Crystal chemical formulas for djerfisherite from structural positions. Izu. Akad Nazk SSSR, Ser. Geol. (4), 97-l0l - and V. V. Ilyukhin (1975)Crystal structureofdjerfisherite. Dokl Akad. Naaft SSSR, 223,343-346. (Crystallogr). Dobrovol'skaya, M. G., A I. Tsepin, L. N. Vyal'sov, I. P. Ilupin, Fig. l. The forward half of the unit cell of K"LiFe*SruCl. Large I. V. Murav'eva, G. V. Basovaand G. P. Belyaevskaya(1975) shaded circles are chlorine atoms, connected to open medium Iron, nickel, and copper isomorphism in djerfisherite.ln F. V. circleswhich are potassium atoms. Large open circlesare sulfur Chukhrov, B. E Borutskii and N. N Mozgova, Eds., Isomorf- atoms. Shadedsmall circlesare iron atoms. The very small open izm Mineraly. Nauka, Moscow, USSR. p. 162-169. circle is the lithium atom. El Goresy, A., N. Grdgler and J. Ottemann (1968) Djerfisherite from the Pena Blanca Springs and Toluca meteorites(abstr.) S lst Annual Meet Meteorit Soc., Cambridge, Massachusetts. Discussion3 and - (1971) Djerfisheritecomposition in Bish- opville, Pena BlancaSprings, St. Marks and Toluca meteorites. Electrochemicallyprepared KuLiFernSr.Clcan be Chem Erde. 30.77-82 consideredas a superstructureof sphaleritewith rela- Fuchs, L. (t966) Djerfisherite,alkali copper-iron sulfide: a new tionships to tetrahedrite(Wuensch, 1964) and pent- mineral from enstatitechondrites. Science. I 53. 166-167. landite. These compounds are cubic with cells about Genkin, A D, N Y. Tronevaand N. N. Zhuravlev(1969) The l0 A. They have, respectively,primitive, body-cen- first occurrencein oresof sulfideof potassium,iron, and copper, djerfisherite Mestorozhd 11, 57-64 (transl. M. tered, and face-centeredlattices. Their asymmetric Ceol. Rud. , Fleischer1970). unit or subcell of about 5 A can be related to the Hall, S. R. and J. M. Stewart (1973) The of -typearrangement with either three or four argentian pentlandite(Fe,Ni),AgS. compared with the refined tetrahedralunits. structureof pentlandite(Fe,Ni)"S. Can. Mineral., 12, 169-177. The structure analysis was based on the formula Hong, H. Y. and H Steinfink (1972) The crystal chemistry of phases K.LiFernSruCl.If electrical neutrality is maintained in the Ba-Fe-S and Se systems.J. Solid State Chem.,5, 93- I 04. and the usual valence states are present, then 23 Fe2+ International Tables for X-ray Crystallography (1962) Vol. 3, could be randomly distributed about the 24 available Kynoch PressBirmingham, England. sites. However, if the stoichiometry is as proposed, Lindqvist, M., D. Lundqvist and A. Westgren(1936) The crystal then this could indicatean averagecharge of l.9l for structure of CoeS6and of pentlandite (Ni,Fe)r,Ss SuenskKemisk Tidskrift, 48, 156-160. the iron atom (assuming S'z The basis for this ). Martin, A. E. (1975) Chemical engineeringdivision-physical in- organic chemistry annual report July 1974-June 1975. U. S. 3 After this paper was submitted the author receivedinformation Natl Tech Inf. Seru., ANL-75-46,30-31. on the work of Dmitrieva (1976), and Dmitrieva and Ilyukhin -, J. E. Battles,F. C. Mrazek, Z.Tomczuk, R. K. Steunen- (1975) on the crystal structure of Khibiny djerfisherite, a = 10.465 berg and D. R Vissers(1974) Chemical engineeringdivision, + 001 A. Their structurediffers from this study in that it contains high-performance batteries for off-peak energy storage, progress magnesiuminstead of lithium and has a statisticaldistribution of report for the period July-December 19'13 U S. Natl Tech.Inf. iron with copper insteadof iron only at sites.Although sodium was Seru. ANL-8057.2l-41. reported, its location in the structure was not established.Never- Mrazek, F. C., and J. E. Battles (1975) Chemical engineering theless,their overall structural details are in reasonableasreement division, high-performance batteries for off-peak energy storage with this study. and electricvehicle propulsion, progressreport for the period TA NI: DJERFISH ERITE-LIKE COM POU.ND 823

July-December1974. U.S Natl. Tech.Inf. Seru.,ANL-75-1 , djerfisheritein the Khibiny massifpegmatites. Geol. Rud' Mes- 9l-100. torozhd.,13,62-71. Nelson,P. A., A. A. Chilenskas,and R. K. Steunenberg(1974) Wuensch,B. J. (1964) The crystal structureof tetrahedrite The needfor developmentof high energybatteries for electric Cu',SboS',.Z Kristallogr, 119,437453. automobiles.U.S. Natl Tech.Inf. Seru.ANL-8075. Sokolova,M. N-, M. G. Dqbrovol'skaya,N. I. Organova,M. E. Manuscriptreceiued, Nouember I,1976; accepled Kazakova,and G. L Vasil'eva(1971) Find and distributionof for publication,March 2, 1977'