Araki, Takaharu

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RIGHT:URL:CITATION:AUTHOR(S):ISSUE DATE:TITLE:The Crystal Structure of Linarite,PbCu(SO_4)(OH)_2Araki, TakaharuAraki, Takaharu. The Crystal Structure of Linarite, PbCu(SO_4)(OH)_2. Memoirs of theCollege of Science, University of Kyoto. Series B 1958, 25(2): 69-791958-12-05http://hdl.handle.net/2433/258105       MEMOXRS OF THE COLLEGE OF SCIENCE, VNIVERSITY OF KYOTO, SERIES B,             Vol. XXV, No. 2 Geology and Mineralogy, Article 1, 2958       The Crystal Stscucture of Lkiarite, PbCu(S04)(OH)2                                    By                            rVakaharu ARAm             Geological and Mineralogical lnstitute, University of Kyoto                           (Received July 21, 1958)                                 Abstract                                                                        e   The lattice constants of the crysta! of Iinarite frorn Kisamori are a==9.67, b=5.64, c==4.68Aand B"102C'401 Its space greup is P2i/m, and there are two rnolecules•per unit cell.   Intensity data were obtained through the oscillation photographing, and the structurewas determined by means of the two-dimensional Patterson, Feurier and difference syntheses.                               Introduction    There are many secondary minerals whose crystal structures were not yetanalysed. For example, a nurnber of sulÅíates containing iron or copper are of thecase.    On linarite from Red Gill, Cumberland, England, only an X-ray study has beenreported by L. G. BERRy (1951) giving the lattice constants, space group and thesÅíructure formula.    Linarite, a basic sulfate Qf lead and copper, PbCu(S04)(OEf)2, occurs widespread-ly in small amount as a secondary mineral in oxidized zones of the copper andlead deposits.    Recently the writer has examined the results of BERRy and determined furtherthe structure of the mineral.                              Experirnental    Specimens from Kisamori mine, Akita prefecture, Japan were used in this in-vestigation. They are prismatic and elongated along b-axis. The unit cell dimen-sions were obtained measuring the distances between the layer lines on rotationphotographs taken with CuKa radiation. The result is:              ooo a == 9.67Å}O.02A, b = 5.64 S O.01A, c== 4.68Å}O.01A, 3 == 102e4e'Å}15' (goniometric)    Density was measured pycnometrically and 5.34 was obtaiRed. Therefore, thereare two chemical linits in the unit ce}1. The space group is P2i/m, OfeO refiexionsbeing present enly when fe k- 2n and the mineral having holohedral symmetry mor-phologically. These resglts are in good agreement with those previously reported•  70 Takaharu ARAKi     The intensity data were obtained, using multiple film technique, by oscillation photographs taken with CuKa radiation and each of the intensities was estimated visually with the aid of a graded iRtensity scale. The usual corrections for Lorentz and polarization factors were applied and the set of Rumbers thus obtained were converted to the absoiute scale applying the Wilson's method to each of the inter- vals divided for sine/7,, but the corrections for the absorption and temperature factors were neglected. These numerical values thus derived were assumed to be the observed structure factors.                          The structure determinatien     In the space group P2i/m, equivalent positions are         4(f) Å}ix, y,z; tc, Y2+y,21 2(e) Å}Ix, 1/4, 21         2(d) 1/2, 0, 1/2; 1/2, 1/2, 1/2. 2(c) 0, 0, 1/2; 0, 1/2, 1/2.         2(b) 1/2, 0, 0; 1/2, 1/2, 0. 2(a) 0, 0, 0; 0, 1/2, 0.     In the Patterson maps it is considered that prominent peaks represent Pb-Pb and Pb-Cu vectors and less prominent are Pb-S, Cu-Cu and Pb-0 vectors. Provided that Pb and Cu atoms occupy the positions of 2(e) respectively, a Pb-Pb vector must appear at 2x, 1/2, 22 and Pb-Cu vectors at y=0 and y==1/2. But if Cu atoms occupy a set of centers and Pb atoms the positions of 2(e), Pb-Cu vectors mttst. appear at pt==1/4.     At the first step of the determinatioR of atomic parameters, two-dimenslonal Patterson syntheses were carried out using observed F2(hfeO), F2(Olel) and F2(hOl) terms respectlvely.     In the Patterson maps which are shown in Fig. 1, there are prominent peaks of different height, i.e. the heighest at y==1/2 and the second at y=-X.itg,. Comparing the peak height of these vectors with that of the orlgin one and also considerlng the weights of the vectors, it was inferred that the heighest peak at y=1/2 re- presents a Pb-Pb vector and the second at y==1/4 a Pb-Cu vector. Therefore the approximate atornic parameters of Pb atoms were easily obtained as x=0.160, N --- 'Y f i5,, 2==0.170, from the Patterson maps projeeted on the (OOI) and (IOO) planes, and taking its coordinates of equivalent positions into account.     Further, it was found that the Pb-Cu vector at y== 1/4 locates just at 1/2-x, 1/4, 1/2-z, where x and z are the approximate parameters of Pb atoms. Consequently it was deduced that Cu atoms are situated at the centers, 2(d). In the Patterson rnap projected on the (01e) plane there appeared only a prominent peak which could be regarded to be an overlap of the Pb-Pb and Pb-Cu vectors. This fact will confirm the deduction above mentioned. Therefore, the space group of linarite was also determined to be P2i/m from the interpretation of the Patterson maps. The other interatomic vectors could, however, hardly be recognlzed due to the background in the Patterson maps.The Crystal Structure of Linarite, PbCu(SO.t)(OH)2 71pmb/2a/2C/2meb/2•IO0             ((Illl])                                           /                                      /a2Fig. 1. The Pattersen maps projected on the (Oel), (10e) and (elO) planes respectively.    Conteurs at an arbitrary unit.72 Tal<aharu ARAI<r    From the parameters for the heavy atoms above obtained the signs of Fo's whosevalues were relatively iarge were easily found taking the contribution of the heavyatoms to the structure factors into account.    At the outset, the electron densities on the <eOl) and (010) planes were evaluat-ed by means of the two-dimensienal Fourier syntheses with Fo's whose signs couldbe determined, and the maxima in the electroR density maps which represent thepositions of Pb atoms were found at the positions close to the approximate positionsobtained through the foregoing Patterson syntheses, wliereas Ctt atoms just at thecenters. Furthermore, the maxima which are regarded to be the positions of Satoms were found, but the Fourier syntheses failed to reso}ve the positions of 0atoms and OH groups.    The coordinates of 0 atoms apd OH groups were then assumed keeping theheavy atoms and S atems in their positions above mentioned respectively and two-dimensional Fourier summatien$ were carried out ttsing F,'s at the intervals of 1/60              bÅë2Fig. 2. Fourier map      dotted. TheprojectedpositionsonofQ                  ''''r"the <Oel) plane. Contours at leeA-2. Zero contours0 atoms and ON groups are indicated by crosses.The Crystal Structure of Linarite, PbCu(SO.,)(Ofl), 73of the cell edgeswiththe aid of Beevers and Lipson strips. The summations wererepeated several times, giving Recessary corrections for t•he atomic coordinates. Forscattering factors Viervoll and Ogrim's values were applyed except for Pb atom,for which values in Internationale Tabeilen were used, and the contribution of Hatoms So the structure factors was negiected.    In Flg. 2 and 3 aye shown the electron density projected on the (eOl) and (010)planes respectively, obtained iR the final summations.    In order to refine the coordinates of the lighter atoms excludiBg the effect ofdiffraction ripples, difference syntheses were carried out, using the differences betweenFo's and F(Pb, Cu)'s, where F(Pb, Cu)'s are the calculated structure factors to whickonly Pb and Cu atoms coBtribute. After repeating this summations, glving necessarycorrections for the coordinates, the maxirna in the eiectron deRsity maps satisfactorilyv---- -s 1itit------t',.Qoo(ISIiliili<IIiijca72Fig. 3. Fourierdotted.map projected en the (010) plane.The positions of S and O atoms andContours atOH groups 10eA-2. Zero contoursare indicated by crosses.74 Takaharu ARAKxcoincided with the coordinates of S and 0 atoms and OH gyeups chosen. In Fig. 4and 5 are shown the electron density projected on the (OOI) and (010) p}anes ob-tained in the final difference summations, respectively.   The coordinates of atoms found in the final syntheses are given in Table 1.             bpa2 / --k  'x  '!1:l 't- t-       -t  --- l-- i- tft -    t- +i    t.t- L/S 1- -tt Jt- ---Si l. .-J-'tt--l-"'--'SiS-"--.-_.-------'i-l-J-r"---..-liNt- : : : t:l "- i-l-- LaLl t-----s -i Å~ i-+L t--t.t.-r'") s 'tr- i-t;- -ttttttL-     S'S t- :    l- sh    t-    -j --  -- - li    d- IS-i - Lr { ......... S.. ..."'''r'  : t "+ N     t -1 -   .lt." 'u. .X "".t -...Ir 'S.sx.S' 1,t"-"i---------'l----t---- -i -- s-i -)   ---tj-tN..s` N: t-l: t""'"n;'-Jtt"-- --J--'t.------   -+  t  ...•"s,  ---+t l-rs-------Il[iS)s sX;lJit--i ;' 1 -:XL N'"--i  :t--    '-He "'x. """' "".. :  .- .-           t-t-----t   -i---t -- ' t """" :b .."... :. S.N :v ! "'. "'           t...".•.v.i ."•..".-'""""'s   t-   :-   :;  l .".."-fFig.t:1':I::Z I)  "N- -'ks-+--         l        t{"     tl"t-_..-_.il /t+t----L-t'S+--s- -----"--"         t       "t--" t--.-At S s i •ttJ S4. The final difference synthesis projected on the (OOI) plane.   4eA-2. Zero contours dotted. The positions of Pb and   marked by cross and solid circles respectively.               Table 1. Ceordinates of atoms. Centours atCu atoms areAtomPbCws0(1)0(2)0(3)Off(i)OH(,)Numbet of atoms in    a unit cell22222422x/a0.1570.5000.8300.9440.654e.8460.3520.455y/b0.250o.oooe.2soe.2so0.250e.o6o0.250o.2seZIge.1680.5000.9980.7740.8340.2480.6990.248The Crystai Structure of Linarite, PbCu(SO,)(OH), 75 --t-ta-tt+L-t--tttt-tJtit9,igtc     Fig. 5. The final difference synthesis projected on the (010) plane. Contours at           4eArm2. Zero conteurs dotted. The pesitions of Pb and Cu atoms are           marked by cross and solid circle respectively.   In Table 2 are summarized the observed and calculated structure factors, thecalculated values being calculated with"atomic coordinates finally obtained and theobserved values being adjusted by multiplying factors which minimumize the relia-bility factors.   The reliability factors are O.l95, 0.200 and 0.286 for ltkQ, Olei and hOl refiexionsrespectively, unobserved reflexioRs being contained in calculations.                           Structure deseriptlon    In Fig. 6 is il}ustrated the structure of linarite.   The structure are composed of the framework of Cu(OU)2 and Pb(S04) chainswhich are stretched along the b-axis, Cu atoms are situated at the center of a space76 Takaharu ARAK!Tab!e 2. 0bserved and calculated styucture factors.hkl l Fo l1002eo300400500l:IlIEEE 46 28213 7e 25F, g Iilel l 600 700 800 90010,00u,oo12,00 020 040 060ilO1201301401501602702iO22023ei:IiiEIftIIIIE203 85 20129 81 24 94129170 7278788332677448946979iE1llilII;LllsIIliIIE  45 - 18- 214 -83 -4 182  58  12- 124 -76 - 24  95- 243 l90- 100 - 94- ilO  99  27 -60- 78 6e- 90 93100liIl•llIlIIIII'ilIIillriIliiill#fII64e65e660710720730740750810820830840850910920 930 940lo,le10,20le,3ole,4G11,le11,20 OOI oe2Fo l 96 23 54 53121Fc24025026027031032033034035036041042043e440450460510520530540550560610620630lilllIIIElii:75624423 69107 21 639784653350 69111 58 646551548224EtIIEliIlIF- 12-  62 64 63- 24  73  26- 242 - 16  73 91131- 88- 53 57  96  99 -68-- 102 -1 68- 47 52- 83- 52il'i:liiIIIIllil'IlIilligIIIilllljO03O04O05011e12013014015021022023024025031032033034035041042043044051052053Eil 27 54 37le3 798614654995 48100 29106 265781315152138 19 46 95 94102 88123130 79 83 96 90122906819120 24 83 61l:IIittl111iiIlIIitI'IL;l:l'l/IilIlfl 134  36 -75 -47- 100 47 43-  34- 79 47 84  8.- 62- 51 55  56- ie3  26 117 -27- 7G 68-  25 54- 57- 137  j.7  37 -69- 104 - 19  82  79- i35 100 63 58- 82 89 94  2-  78- 65 38- 25- 113   3 -56 -76 -16The Crystal Strttcture ef Linarite, PbCu(SO,)(OH>,Table 2. (Continued)hel l Fe i Fc1li 5755623845ili:1R05406106206307110110i20120I30130140140150150I6el60i701701801 80-1 9el 9e-110,0110,0I11,0111,el22,01 102 1022022023023024024025e2502602602702702802802902 90210,0210,0221,0212,e2i{iltIIIIIlIirl:1ll'}l;iiiIiIIIIL 49258l40 28 99 32 32145147 29 68 251341204461262295 78 5142154 90 73120 28 48127 48105 47119 20 57 89 11 55105 93 51hel l Fe I Fciil11111ijiiIllj:IiiIIIIIii/III 69- 83 72 51 60  11 2e2-  i80   4 -7e -5 -27- i67 i29 -7  64   3  2e l44- 212  32 -62  12- 32- S02  91 -44 -24- 177  33- 36147- 12 38144  27  62- 149  le -45- 115 -14 -49 le6 -38 51106 51- 88- 41IlIlIIFI1llIiIIiIlIIii'll•1lilill11lllli'lEIIIi'llIiIlIiIII:Il[iEIIlliIIIl[lilililiil'liillilIiIals,l''t/103log2032og3033og4oe403503sog6036og7e37og803 sog 903 goglo,eglgog1041042042043043044044045e45046e46047e47e4804 904le,e4 105 205 2052e530530S40540$50560S70S805Fi:]II:11lliilII 43 63 20!0963522590643646 31le5 73 64 48162126 24 44127125 46469342 83103 10104 46 36 90 2097513877i:iII[I!iII,lIil'- 30- 12- 6  5124123 37 31 37- 5 -98- 115 -38 - 47 -31- 23 76 95 54 40  38- 225 121 -28  ll -33 -4 105- 103  58- 19 27  3- 98- 58- 53 71127- 8 25- 12i -25 -47- 2e5 -5 131  57  25- 1107778 Takaharu ARAKI S Ctt Pb OH   oFig. 6. The structure of linarite projected on the (010) plane.Table 3. Interatemic distances.Atom Atom l Distance (A) l        llS MOis -o.S --t 03Cu -- Ol1' iCu -- OH,Cu -- 02Pb -O,Pb - 0,'Pb _....0,Pb ttt. O,,Pb ".. O,t!ill:t1.681.711.572.201,822.372.453.022.603.223.391 Atom AtomU.t...t  OH,mm OHpm- OHI'ww 02ua 02_ 03_ 03un 03rr.  03'--  e"". ..n 01'IPbPbPbPboi02Oi030i0i0iDistance (A) 12.772.823.193a362.882.602.812.l42.662.703.55lI1Atom Atom1I o, - o,'!I' 02 ww 03'I o, .t........t o,, 0, ww OH,I 02 - OHItI 02 -- OHi"I O, - oll,l 03 ww OHiI Off,--- OH,I OH,-- OHd OHi - OH12,ill       oDistance (A)' tt   4.11   3.79   3.42   3.75   2.85   3.58   3.01   2.64   2.52   2.54   3,36These values imply the errOrS      ooÅí +O.03A resulted from the termination effect.                 The Crystal Structure of Linarite, PbCu(S04)(OH)2 79surrounded by four OH groups which are coordinated in a plaRe, whereas Pb atornsare situated at the positlons close to two S04 groups in a space surrounded by fiveS04 and two Oll groups.    The interatorr}ic distaRces are tabulated in Table 3.                             Aeknowledgment    ']rhe writer wishes to express his sincere thanks to Dr. T. ITo and Dr. T. UEDA,who gave him va}uable advices throughout this work.                               ReÅíerencesBERRy, L. G.: Am. Min., 36, 511 (1951).PALAcNE, C., BERMAN, H. and FRoNDEL, C.: Dana's system of mineralogy, 7th ed., II, 553       (i951).ITo, T. and SAKuRAr, K.: Wada's minerals of Japan, 3rd ed., 334 (1947).

The Crystal Structure of Linarite, PbCu(SO_4)(OH)_2

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The Crystal Structure of Linarite, PbCu(SO_4)(OH)_2

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