CanadianMineralogist Vol. 28,pp. 751-755(1990)

REVISED UNIT-CELL DIMENSIONS, SPACE GROUP, AND CHEMICAL FORMULA OF SOME METALLIC

PETERBAYLISS Department of Geologlt ond Geophysics, University of Calgary, Calgary" Alberta T2N IN4

ABSTRACT tion File by Baylisset ol. (L986),inconsistencies were found between the crystal structure of a synthetic New data are given for algodonite (formula), awaruite compound given in the literature or deducedfrom (formula, spacegroup), billingsleyite(space group, unit the structure-tlpe and the chemicalformula of some cell), bogdanovite (formula, space group), hexatestibio- metallic mineralsas given by Fleischer(1987). The panickelite (formula), keithconnire (formula), mgriite purposeof this paper is to tabulate correctionsfor (formula), polarite (formula), (space group), roaldite the unit-cell dimensions,space groups, and structuml sobolevskite (space groups, unit cells), stibiopalladinite minerals. (space group, unit cell), stiitzite (formula), urvantsevite chemicalformulae of some metallic (spacegroup, unit ce[), wairauite (spacegroup), and weis- site (spacegroup, unit cell). The structure-tlpe AuCu, tetra- Mntrroos auricupride, is shown to have the Pearson Symbol Code of tP2 rather than tP4, so that a(lP4) : r2a(f2). New In many simple metallic minerals, the possible unit-cell dimensions are given for four minerals (tetra- structure-typesare limited. In eachof the possible auricupride, tetraferroplatinum, ferronickelplatinum, and structure-types,the majority of the atoms have all tulameenite) and 19 metals in tP2 rather tharL tP4. or someatomic coordinatesin fixed positions. From each possible structure-type or a crystal structure Keywords: algodonite, awaruite, billingsleyite, bogdauov- given X-ray vite, ferronickelplatinum, hexatestibiopanickelite,keith- in the literature, the intensitiesof the connite, mgriile, polarite, roaldite, sobolevskite,stibio- powder-diffraction reflections were calculated with palladinite, stiitzite, tetra-auricupride, tetraferro- POWD (Snith & Smith 1987).The calculatedinten- platinum, tulameenite,urvant-sevite, wairauite, weissite. sities were compared to the observed intensities of the X-ray powder-diffraction reflections found in the SovrMnrns literature. Some ftkl indices of the observed X-ray powder-diffraction reflections were set, then a least- Des donn€es nouvelles sont d6crites pour l'algodonite squares unit-cell refinement @ayliss 1989) gave (formule), awaruite (formule, groupe spatial), billingsleyite improved unit-cell dimensions.Further ftkl indices (groupe spatial, maille 6l6mentaire),bogdanovite (formule, of the observedX-ray powderdiffraction reflections groupe (formule), spatial), hexatestibiopanickelite keith- were set, followed by further least-squaresunit-cell connite (formule), mgriite (formule), polarite (formule), of cell dimen- roaldite (groupe spatial), sobolevskite (groupes spatiaux, refinements, until the refinement the mailles 6l6mentaires), stiitzite (formule), urvantsevite sions was complete. When the calculated and Groupe spatial, maille 6l6mentaire),wairauite (groupe spa- observedintensities of the powder-diffraction re- tial), et weissite (Croupe spatial, maille 6l6mentaire). La flections matched completely, then the chemical structure de type AuCu, t6tra-auricupride,aurait le symbole formula, spacegroup, crystal-structuretype, and de Pearson de tP2 plutOt qluetP4, de sorte que a(tP4) : unit-cell dimensionswere consideredestablished. i2a(tP2). De nouvelles mailles €l6mentairespour quatre mindraux (t6tra-auricupride, t6traferroplatine, ferronickel- RESULTS platine et tulameenite) et dix-neuf metaux sont exprimds dans le groupe lP2 plutdt que tPA. The revisedunit-cell dimensions,space group, and (Traduit par la R6daction) chemicalformula of somemetallic mineralsare listed in Table l. Sincethe chemicalelements cannot be Mots-cl8: algodonite, awaruite, billingsleyite,bogdanovite, subdivided into cations and anions, becausethe ferronickelplatine,hexatestibiopanickelite, keithconnite, minerals have metallic bonding, the chemicalfor- mgriite, polarite, roaldite, sobolevskite,stibiopalladi- mulae have beenlisted in alphabetical order, except nite, stiitzite, tdtra-auricupride, t6traferroplatine, tula- that only the first elementin parentheseshas been meenite, urvantsevite, wairauite, weissite. considered. The PSC in Table I representsthe Pearson Symbol Code, which was describedby INTRoDUCTIoN Hubbard & Calvert (1981),and hasthree parfs: The frst letter representsthe , where c is During a review of the Powder Diffrac- cubic,& is hexagonal,/is tetragonal,o is orthorhom- 751 752 THE CANADIAN MINERALOGIST

TABLE 1. REulsED PEjARSoN sr}lBolr CODE, cI$r'{IcAL FoRMt[;[, SPACE GROUP, AND IJNIT-CELL DIMEITSIONS

chenlcal spaca PDF l'linsaL PSc fomla eioup a(A) D(A) c(A) No.

Algodonlte hP2 Asxcul-x P6)lnnc 9-429 Auanlt€ hP4 FeNi3 Pm3m 38-4 19 Bll-l1ng6l6ylte cP56 Ag7AsS6, P2t3 10.4s1(4) 2L-L3?4 Bogdanovl,te cP4 Auacu PnSn 4.0876(15) 34-1302 nexatestibiopanickelite hPA NtiTe,sb) P63/mc 3.983(3) 5.339 (3) 29-932 Kel"thcomLte hR27 Pd2gTeT R3 11.4s8(10) LL.296(12) 34-!46L llgrrltte ctr8 (Se,Cu,Aa) Fd3n ?5-675 Polarite oc32 BIFbFd2 Cm2y 7.14(13) 8.656(17) 10.501(16) 23-L294 Roaldite clP5 fe4N P43m 6-627 bP4 rBlPd P63lmc 4.22O(L7) 5.709 (4) sobolevskLte nc32 p-BiPd B2t 7.t6(2, 10. 66 ( 5) 8.74 (2) 29-234 P=90" s!lblopalLadlnlte hP42 Pdssb2 P63cn 7.606(11) L4.2rG) 25-597 stUtzite hP55 Ag7Ie4 P6/M 18-11S7 Unantsevite tI6 P-Bi2Pd 14/m 3.3628(16) L2.9O2(LL) 29-232 walraulte cP2 CoFe Pn3n 2.a57 w€lssite hYt2 Cu2-xTe P3a]. S.342(15) 2L.69 (9) LO-42L Tetra-aurlcuprlde tP2 Aucu F4lwm 2.800 3.670 25-L220 Tetraferroplatlnm tP2 I'ePt P4lnan 2.7235(LOt 3.720(3) 26-LL39 Ferronlckelplatlnm tPz (Nl,r€)Pt PAlnan 2.7X1,(3, 3.541(8) 35-702 lulueenit€ tPz (Cu,Fe)Pt P4/nnn 2.7477 (4) 3.5870(8) 26-528

Psc Pearson slmbol code PDF No. Powds Diffractlon Fll€ nmb€r

bic, ru is monoclinic, and a is anofihic (triclinic). The is As"Cu1-", although metallurgists prefer secondletter representsthe Bravaislattice, whereP As6.2eCu1.r1so that it may be sorted in metallurgical is primitive,.Iis body-centered,Fis all facescenterd, alphabeticalformula indices. Such indices will be Cis one face centered,and R is rhombohedral.The produced by JCPDS - International Center for number representsthe number of atomic siteswithin Diffraction Data in ils new Metals and Alloys data the unit cell. compilation scheduledfor production in 1991. Awaruite is isostructuralwith isoferroplatinum, DrscussroN FePtr. Sinceall atomic positionsare fully occupied with Fe in the fixed atomic position la at (0,0,0)and Algodonite is isostructural with allargentum, Ni in the fixed ltomic positions 3c at (0,0.5,0.5)in Agr-.rSbr.Since the 2(Cu,As) atoms (Cu:As : 6:l; spacegroup Pr?r3rn,the correct formula for awaruite Naud & Priest 1972)completely occupy the fixed is FeNi3(Lutts & Gielen 1970).The Ni-Fe ordering atomic positions 2c at (0.333,0,667,0.25)in space is shownby the 100and I l0 reflections,which both gtotrp PE/mmc, the correct formula for algodonite havea calculatedrelative intensity of only 0.4 com- pared to 100 for the most intensereflection. Billingsleyite, Ag"AsSo,described by Frondel & Honea (1968) in the orthorhombic space-group TEBI]E 2. X-RAY POI{DER-DIT'FRACTION DATA OF SOBOLEVAKITE C222.t,with Z : 8, has .F2, : 7(0.047,78)accord- soboLevEkite d-BLPd p-BlPd ing to Smith & Snyder(1979), where 7 is the observed dobe number of reflections (25) divided by the possible t numberof independentreflections (78) and by delta 3.65 67 20 (0.047). Least-squaresanalysis of billingsleyite in 3. 07 100 3.08 2A cubic space-groupP213 (the low-temperaturephase 2.69 20 2.64 100 2.53 23 qf Blachnik & Wickel 1980)gave at o of 10.481(4) 2.26 100 2.25 100 2.27 L6 2.r9 10 2.145 49 A with Z : 4, to give a significantly higher Fx at 2.rL 90 2.LL 63 1.800 8 l7(0.049,30). I.74 40 I.74 26 Bogdanovite was described by Spiridonov & L.69 50 L.69 24 L.69 L7 I.642 10 1.648 12 Chvileva (1979)as a cubic mineral with a small unit- r.541 30 1.539 19 cell dimension. This suggeststhat bogdanovite is L.492 isostructural with isoferroplatinum, FePt3. Least- 1.450 10 L.43 20 L.427 4 r.40 squaresanalysis of bogdanoviteyielded a unit-cell 40 1.321 20 dimensionof 4.0876(15)A in spacegroup Pm3m, L.244 40 L.243 L4 L.23L which suggestsa formula of (Au,Te,Pb)3(Cu,Fe), 1.218 20 50 1.182 10 L.179 with Z = l. The Au fully occupiesthe fixed atomic r.Lr1 40 1.118 L2 (0,0.5,0.5), the 1.09 20 1.089 positions3c at and the Cu occupies 1.065 20 1.065 fixed atomic position la at (0,0,0). 0.99a 10 0.998 Hexatestibiopanickelite@latinum Metal Mineral REVISED DATA ON METALLIC MINERALS 753

ResearchGroup, 1974)is isostructuralwith nickeline, IABI;B 3. I'NTT.CET;L.DIMEIISIONS OF IiIETAIS IN SfRUCTURE TYPE IP2 NiAs (Hewitt 1948).Since all the atomic positions are fully occupiedwith (Ni0.6ePd0.r,)in fixed atomic a (A) c (A) positions2a at (0,0,0)and (Ie6.r6Sbs.asBio.or)in fixed ASTi 2 .9014( 18) 4.066(4) 6-560 A1Pu3 3.1736(18) 4.534 (4) L9-4L atomic positions 2c at (0.333,0,667,0.25)in space AlTi 2.ArA5g) 4.0803 (8) 5-674 group Au3Pe 2.777r(!31 3.880(4) 15-43 P6r/mmc, the correct formula of BtTt 3.367(3' 4.256(5) 21-422 hexatestibiopanickeliteis Ni(Te,Sb) with Z : 2. CaPb 3.6159(13) 4.4SS5(19) ?2-L69 calHg 3.943(4) 2.8855(24' A-317 Imgreite, NiTe, has been rejectedby the Interna- calPat 3.0253(e) 3.62OO(L7) 6-570 cdPt 2 .9565(10) 3.825(3) L4-7 tional Mineralogical Association ( & Mandar- FePd 2.7255(2Ol 3.720 (3' 2-r44O ino 1987). sgNi 2.982(31 3.139 (3) 31-853 ggFt 2.97 04 (1,9' 3.813(4) 6-572 Keithconnite was originally described by Cabri gg3Ti3zn 2.9275(2!) 4.045(4) 22-L253 (1979) : Inldg 3 .23L6(6) 4.3939 (16) 1e-583 et al. as Pd3_"Te,wilh Z 7. The observed InPu 3.4013 (5) 4.527 (3) La-62L X-ray powder-diffraction data are similar to those IrV 2.7465(25) 3. 647 (11) 29-692 ltng.55RhSb9.45 2 .9568(11) 3.47L(4' 32-39 calculatedfrom the crystalstructure of Wopersnow PdZn 2.4944(71 3.372 (X' 6-620 & Schubert (1977), so that the correct chemical PtZn 2.8461(8 ) 3.492(3) 6-604 formula is Pd26Tq, wilh Z = I in spacegroup R3. Mgriite (Dymkov et al. 1982)is isostructural with silicon and diamond. Majid & Hussain(1987) gaye (Se6.rCuo.rr5As6.,rr)with a : 5.5^30 A, B anglewrs set at 90ofor the least-squaresanalysis, (See.rCuo.2rAs6.25)with a = 5^.515A, and the resultsof which are reportedin Table 2. There- Se6.a3Cu6.n3Aso.rnwith a = 5.758 A for synthetic fore, sobolevskiteis considereda mixture of the two phases. Since all the atomic positions are fully BiPd polymorphs. occupiedin fixed atomic positions 8a at (0,0,0) in Stibiopalladinite, Pdjsb2, is isostructural with spacegroup Fd3m, the correct formula of mgriite orcelite, NirAs2. The crystal structure of PdrSb2in is (See.a23Cue.a15Ase.l3eFes.sx),with Z : 8. spacegroup P63cmhasbeen described by El-Boragy Polarite, which was studied by Genkin el a/. et sl. (1970), wilh Z = 6. (1969),has an empirical formula Bit.0lPbr.04Pd1.e5. Stiitzite (Stumpfl & Rucklidge 1968) has been The phase diagram BiPd-PbPd of Mayer et al. attributed a chemicalformula of Agr-"Te3 wrlh Z = (1979) shows a distinct phase of stoichiometry 7; however, the crystal-structureanalysis of Imamov BiPbPd2,whose crystal structureshows the Bi and & Pinsker (1966)gives AgTTea wrth Z : 5 in space Pb in different atomic sitesin spacegroup Ccm2,. group P6/mmm. The published calculatedpattern @DF 33-207) is Urvantsevite, B-Bi2Pd, is the high-temperature similar to the observedpattern @DF 23-1298)of polymorph of froodite, o-Bi2Pd (Brasier & polarite, so that the chemicalformula of polarite is Hume-Rothery 1959). The crystal structure of BiPbPd2. Polarite describedby Tarkian (1987)as B-BrrPd in space group l4/mmra has been con- Pb-free, but without X-ray powder-diffraction data, firmed by Zhuravlev & Zhdanov (1953). probably is sobolevskite,BiPd. Wairauite is isostructural with CsCl. Sincethe Co Roaldite, FeaN, is isostructural with the synthetic atom fully occupiesthe fixed position la at (0,0,0), phaseFeoC @insker & Kaverin 1956).The N fully and the Fe atom fully occupiesthe fixed position lb occupiesa fixed atomic position la at (0,0,0) and at (0;5,0.5,0.5)in spacegroup Pm3m, the chemical the Fe fully occupies atomic positions 4e at formula is CoFe (Ellis & Greiner l94l), with Z : (0.265,0.265,0.265)in spacegroup P43m,so that the l. The Co-Fe ordering is shown by the 100reflec- formula of roaldite is FeaN, with Z : l. tion, which has a calculatedrelative intensity of only Sobolevskite,cr-BiPd, was originally describedby 0.02compared to 100for the most intensereflection. Evstigneeva et al. (L975) as isostructural with Weissite, Cu2-"Te, with Z : Vl, has a crystal nickeline, NiAs. A calculated X-ray powder- structure in space group Hml @aranova et al. diffraction pattern in space grottp PQ/mmc, wrth 1974).Of the 36 atomic sitesin the crystalstructure, Pd in fixed atomic positions2a at (0,0,0) and Bi in three of the 3d atomic silesare exactlyhalf-filled with fixed atomicpositions 2c at (0,333,0.667,0,25)com- Cu. The exact formula of Cuor.rTe2nwith Z = | pared to the observed powder-diffraction data, may be expressedas Cut.6125Tewfih Z : V[, so that accountsfor only 12reflections. Therefore, there are x : 0.1875in Cu2_,Te. nine additional reflections. A calculated X-ray Tetra-auricupride,AuCu, is grvenas the structure- powder-diffraction pattern (PDF 33-213)based on type tP4 by Villars & Calvert (1985). The fixed the crystal structure of Bhatt & Schubert(1979) in atomic positions are Au in lo al (0,0,0), Au in lc spacegxoup B2r, with the chemical formula B-BiPd at (0.5,0.5,0),and Cu in 2e at (0,0.5,0.5)in space and Z = 16,accounts for the additional nine reflec- group P4/mmm. If the atomic positions la and Lc tions. Sincethe B angle of B-BiPd at 90.3ois close haveequivalent occupancies, then the structuretype to 90o and the number of reflections is small. the /P4 becomeslP2, with the fixed atomic positionsof 754 THE CANADIAN MINERALOGIST

Au in la at (0,0,0)and Cu in ld at (0.5,0.5,0.5), Bnasmn,J. & Hurue-Rorunnv,W. (1959):The equilib- where a(tP{) : ,l2a(tn). Similarly, tetraferro- rium diagramof the systembismuth-palladium. .I. platinum, FePt, belongslo tn, just as potarite, Less-CommonMetals l, 157-164. HgPd. Casru,L.J., RowLANo,J.F., Laruauue, J.H.G. & Tulameenite,(Cu,Fe)Pt, doesnot show the addi- Srrwanr, J.M. (1979): Keithconnite,telluropal- tional reflectionsto indicate ordering of Cu and Fe ladinite and other Pd-Pt tellurides from the Still- for the structure-type tP4. A calculated pattern of water Complex, Montana. Can. Mineral. 17, CuFePt2 in structure-type tP4 and in spacegroup 589-594. P4/mmm showsthat the strongestreflection not in the (Cu,Fe)Pt structure type tP2,is the 100 reflec- Dvvxov, Yu.M., LosBve,T.1., Zsv'uN-ov,E.N., tion, with an intensity of only 0.1 comparedto 100 Ryznov, B.I. & Bocurr, L.I. (1982):Mgriite, for the most intensereflection. Similarly, ferronickel- (Cu,Fe)3AsSe3,a new mineral. Zap. Vsu. Mineral. platinum, (Ni,Fe)Pt, doesnot show the additional Obshchest.lll, 215-219(in Russ.). reflectionsto indicate ordering of Ni and Fe in the (1970): structure-type /P4. Becausethe crystal-chemistry Er-Bonacv, M., BHAN,S. & Scnugsnr,K. properties Kristallstruktur von Pd5Sb2und Ni5Aq und einigen of the transition elementsFe, Co, Ni and Variaten.J. Less-CommonMetals 22, M5-458, Cu are similar',atomic orderingis unlikely to occur. Additional mineral speciesnames should noi be given Errrs, W.C. & Gnrnmn,E.S. (1941):Equilibrium rela- until ordering has been proven. tions in the solid stateof the -cobalt system. A review of metals with the structure-type /P4 in Trans.Am. Soc,Metals 29,415-434. the Powder Diffraction File showedthat a further 19 metalsout of Z could be satisfactorilyindexed Evs'rrcNsrva,T.L., GsNKrN,A.D. & Kovalemrrn, in the structure-type tY2. The new unit cell dimen- V.A. (1975): A new bismuthide of palladium, the nomenclatureof mineralsof sions of thesemetals are listed in Table 3. sobolevskite,and the systemPdBi-PdTe-PdSb. Zap. Vses.Minerql. Obshchest.104, 568-579(in Russ.). ACKNoWLEDGEMENTS Fr.srscuEn,M. (1987): Glossary of Mineral Species. MineralogicalRecord, Tucson, Arizona. Financial support was provided by the Natural Sciences and Engineering Research Council of Fnouorl, C. & Homea,R.M. (1968):Billingsleyite, a Canada. Dr. L. Calvert and anonymousreferees are new silversulfosalt. Am. Mineral. 53, 179l-1798. thanked for critical reviews. GsNKIl,l,A.D., Evsrrcrrrve, T.L., Tnornva, N.V. & Vval'sov, L.N. (1969):Polarite Pd(Pb,Bi) - a new mineral from -nickelsulfide orex.Zap. Vses. REFERENCES Mineral. Obshchest.9E,708-715 (in Russ.).

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