M. Granger decribed the preparation and the properties of mercury phosphide Hg3P4. The present authors repeated Granger\u27s experiments and obtrained a crystallized compound showing the same properties but with a composition given by the formula: Hg3P2l2. No compound which contained only phosphorus and mercury could be obtained by the method described

D. Grdenić

M. Kesler

S. Šćavničar

English

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AR H IV Z A KEM I J U 24 (1952) 61 On the Mercury Phospboiodide HgJP2h iD. GRDENic, S. SCA VNicAR .an,d M. KESL·ER M. Graingeir1l de.criibed the pre:paraltion and rhe p1101pertie,s of imel'aury iphosiphide Hg3P4:. The p:res.ent auithoDs repe.a'ted Gran1ge.r's ·experiments and oibtruiJrued a crys.taJili,zed <eompo1und sho1wiing the sa1me proper!Ji1es but witih a composition g:irven by the 1formula: Hg3P2l2. No OOIIIJiP1cmnd whfoh oorrilt>aiiined on~y 1pihosipihoa:ms e1JJJd me1l:'cmy coruilld be obtaiined thy the metihod desior·~bed. The orysta1s air·e moinodinik, :belongiin:g to ·the .space ,gaioru1p C25h-P21/c. The eleimental!'y cei11 oontia1niing 1121 stokhiioimetric uni:ts Hg~P2h has the d:imensi'1on1s·. a= 13.07 A b = 12.44 A c=l7.16A ~ = 120.20 The imethoid of ip1repa:r.aition !l!rud anallysi\<;1, .the chy.s1tailL01g1ra1phic · •and chemi1cal d.aita Olf ·the 1s:U1bstairuce Me gh,ein. The i111Vesti1g.atilions of ~ts stmc!JUlr·e 1by X-ray me:thods is in progress. The crysta1 chemistry of mercury compounds, with the efoments. of the 'Sb subgroup is better known only in the case of nitr:o1gen. From the mer-cury compounds with arsenic on!ly the crystal structure of (Bu3Aslzi(HgBr2) 2 has hitherto been investigated2) and its As-Hg bond length detennined. The bond length P-Hg is still unkno.wn. In order to de1termine this bond length we chose the compound desaiibed by Granger1) as Hig3p 4, he•causie the other mercury phosphides quoted in chemical literatu.re3} do noit occur in crystals. Granger's compound is described i1n Abe1gg's handbook4} and it iis merut:ioned also in Groith's wo:tik5l. The oompolli111d se•euned to be very inter-sting and we beHeve·d that a knowledge with ,iif:s structure would ialso be of some importance for the crystal chemistry of the metal phosphides. The compound was prepared according to the Granger's method by hea1ting mercury and diphosphorus teitraiiodi:de in a sealed glass tuibe. Single crystals suHable for crysta.J.lographic me1asurements are _very rare. We succeded in obtaining only a few examples about 1 mm long and 0,5 mm thick. The crystals have a high metailic lustre arn.d a dark vio'let colour. They may be easily powdered to a re·ddish brown powder, but no cleavage hais been ·oibserved. Thi:n crysrt:a1s viewed hy transmitted ;light are ruby red. After Gran,ger's de1s1cription ·the crysfal habit 1is hexagonal. Ouir crystals have also sU1ch a haibit, ibU1t the goniometric and men1tgeno.graphiic measu-rements showed that the crystals were really monoclinic prisms elongated 1) M. G rang e r, Ainin:. cMIIll. phys., [VU] 1.4 (1898) 5. 2) R. C. Evans, F. G . M:,a;nn, H. S. Pebser a1IJ:d D. Pull'd .~.e, J. Chem. Soc., 1940, 1209. 3) L. Mos e il' aind A. Bir ill ,k I, Z. ano11g. all1g. Chem., 121 (1922) 252, described :amorphous p1recdip~t.a1tes of Hg3,P and Hg3P:i. 4) K A 1b ·e ,g g, Hanclib'lUch der arumg.ani~s1cihen Chemi·e, 11, 2, Le~pzig 1905, p. 633. 5) P. Groth, Chemiische Kiryi&taU01gra;phi1e, I, Leipzig 1906, p. 60. 62 D. GRIDENIC, S. SCAVN!ICAR and M. KESLER in the cliredion of the b-axis (Fig. 1). The following faces were always; observed: { 100 }, { 001 }, {102}, {111 }, { 111}, and ocrusioniaUy { 010 },, { 110 }, { 011 }, {101 }, { 021 }, { 112 }, l22 }, {211}, and {212 }. The axks ra1tfo i1s a1:b:c = 1 ·058 : 1 : 1 ·358 (£rom unit ooLl edges determined by X-rra:y method: a:b:c = 1·051 : 1 : 1·379). a We attempted to grow the ·crystals by sublima-tion in an atmosphere of cal'bon dioxide in a sealed gilass tube by a method which was in principle similar to that already described by Ruston and RiidorfN but with no suc1cess. The sublimation was accompanied. by ·de.composition and only small crystals were obtained. The products of the decomposition attracted' our attention and in mder to s'trudy them the follo-wing experiments were performed. The substance was heated seve:ral hours in a sealed glass tube filled with dry caflbon dioxide. The temp~rature was ,kept constant 250°C at the bottom and 150°C at the top· of the tube. The products of the decomposition were mercurry, pJmsphorus 1f whie1h usually burst into flames wihen the tube was opened) and big, tetragonal, yellow crystals of mercurous iodide. Under 'those con-ditions no other products of the decompositions could be observed. ' The chemkal analysis was carried out on several examples from different ip1repara'tions and gave the brutto formula Hg3P 2I2 • The equation for the de-composition is therefore 2 HgaP2I2 = 2 Hg + P4'+2 Hg2I2 A !lllittte1 ih:i!ghe•r vail.ue1s for meiricurry werr.e obtaiin1ed. Jhis may be explained by the fact 'that the usual methods of cleaning (recrystallisation and sublimation) could not be applied. The impurities may be mechanical or enclosed in the crystal lattice during 'the growing of crystals. · All the chemical properties of our crystals. are the same a.is described by Granger for Ms phosphide. In. addition, the particular resistance again·st nitdc acid may be pointed out. The. fuming ·nitric add acfa very slowly even on heating under reflux. When we begati the investigation we assumed thait Hg3P 2I2 probably contained a P-P bond and that it was necessary for its preparation to take diphosphoms tetra:iodide. It was shown, howeve·r, tha1t this is no•t the ca1se sir.ce the reaction of the phosphorus trHodide with mercury, carril'!d out in the same manner, gave the same product. As for the structux-e of Hg3P 2I2,· no, definite conclusions can be made at present, but it is very- prohahae that mercury phosphoiodide 11s amafogous to a meTcury n:itmgen compound be'longing to the group of !'1-iHon's base 6) W . R. Ru s t ,on and W. R ii do rf f, BuM. soic. chim. Edges,, 56 (1947) 97. MERCURY PHOSPHOIODWE 63 salts. If this asumption i,s Via.lid the correct formula would be [Hg3P21]+ l-and the compound is a me.rcury-iodopho1sphonium iodide. But we .do not exclude other possiibilities and detailed X-ray analysis will dedde. The, unit ce~l and the space group was determined by the 111sua1l X-ray method using osdlilation pihoto1gr.aphs. The filtered CuK radiation was used. The unit cell has the dimensions a = 13·07 A b = 12·44 A c=17·16A The density determined picnometr.ica1ly .i:s 7·69 g. cm:-3, The unit cell con-tains therefore 12 stoichiomeitric units of Hg3P 212 (the calculate,d deniS.ity iiS 7·62 g. crn-3). The reflexions with mdiJOes hkl were all olhs·erved. Absent reFlexii01I1s we11e OkO for k oidid a1I11d hO! for l 01did. Toos the sp.aise grorurp is c~h -.P21/c. EXPERIMENTAL 1 J Preparation of H g3P 2! 2 • 1l1I1 a har'd glass tuJbe (2 am il!l diameter and 30 cm in ·d.enig'tih) the diiphosiph01rus tetraiodiiidie (20 ,g) amid merC'Ulry (40 g) were introduced anrd the air expelled with dry carbon dioxide. The1tU1bewas then sea:led aind hea1ted for 10 hout:s -ocm.ti1rnua11y in .an ah1anin'l.linl bloick. The temperaiture wai.s· miadtntaiin1ed constant and amQIUJI1'ted to 330-340°C at the bottom and 250°C in ·the middle of the tuJbe. Swoh a ·temperature gradient is 111ecess;ary for the s.epar<l!tion oif ireactfo1I11 prodrucrbs. The tube mus.t be cooled ,siJ.:owly (2-3 hour:s). The fower part of rtrhe tuibe walS ·fiiilled witih the' crust of .small crystals of Hg3P2l2 mixed witrh mercurours iodide, drops of mercury a:nd a1 Hrt;tle scatilet amor:phous phosphorus. The upper pa:rt was BHed w.Hh o~an!ge and yeil:lorw crysrtails with the mercurous ii101dide as the mruin c·ormponent. But they conta:ined also mercuriic 'iodide an1d probably the no1I11de£in1ed compOU!lllds of urn.changed phospho1ru:s iod~de wi:th mercu~ iod!irdes7). The cry1srt:al crust wa·s ground, m:iixed wi.Jth pofa1ssUiurrn iodide. (20 g), water wa.s added, ·the predpitate warmed on a water bath and washed by decaritation. The residual! mercury was diss·olved .by warming wlith dilute nitric <l!cid (20°/o) 01I1 a wa.rtex lbath. The nitric add wa's reinewed 5 times each hour. The prrod:uct wais1 ~ashed wirth waiter a:nd a1lcohol anid' dried on a water bath. The yield Wia.1s 28 ,g or 8810/o of the 0a1lcUilaiWd, amort.llilt. 2) Preparation of the crystals. Since an ruttemrprt to ,gll'ow the crysta1l1s · £rom the pwre pmduct by s'Ulblimarbi.o[)J ga~e no results, we tried to obtruin sin:gte crysfals diredly from the reaction of the prerpar.aition in the tube·. For thiis purpose man.ry prepiairations were carnried O!Wt by the meit.ho1d descri--bed aibove but only a tenth of thait quantity was :taken. The di:merns~Olllis of the ~la·ss t111be were thus sU!i.taibly redU1Ced (1 cm in diameter a1I1id 20 am in },eng:th). Onil.y a few weli ,dev;eloped crysta.Jls wel."e obtaigi~d· a:s a re·sult Olf many pre:para:tiOJns. 7) A y.ellJLoiw merciu1ry phosphorns j,odide Hrg2Pl3 wa1s aiLlreardy p·repared by Ven-turoli 3Jlld w~s descr1ibed by 0. D a mm e r, H aindbuch der anorgam-ischen Chemie , n. 2, S>ruttg:airt 1894, P· 919. 64 D. GRDENIC, S. $CA VNlICAR and M. KESLER · 3) Chemical analysis. The method accoodirng to Volhaivd.8) gave rulways a mercury sulplriide conta.!iiniing :phorsphorus. Therefore a moclifile:d SOUJberain . amid L:reibi1g·'1s•9 ) method wa1s appH1ed. The srtlibsfaJnce was miiXed. w1i:th a finely powdere.d mixture of sodiUJm hydrox·1de a:nd maigne1sium oxi:de (2 : 1). The read.lion wais 1crurried out m a iloillig glass test tuJbe:. The test fat1be wias filled as foil!low1s1• At fiirst the pure mixt1111e of sodii!tllm hyid.m:ride aiDJd magonesiiium oxide was. mitriod~ced, then •this miadure plus: sUJbstaince, aigaiiJn prttire mixture, then mixture of magnesilUlIIl oxide wHh sodium peroxide and finailly a few a1S1be:stos filbr.es. The test tuJbe was then ·drawn am:d ibent three times ait right amigiles:. T!he mJilddle part wais blown to a ibu~b i:n or.der to se:rve as reoiipienit: for me:rcury and waiter. The herutiing 1be:gan fo-om the: aislbesrtos. t:o-Wait"ds the end of the test tube. After the mam prurt of the mercury was diilstii!l~led, the whoile ma:ss wa:s hooted' •strongly io expel! the farsit traces of mer·cury. The •bUJllb with the mercury wa,s cut off, the mercury dissolved in a little cllilute nitric acid and determined a1s sulphide. The ites:t tuibe still warnn was fowereid illl cd],d water aJnd ·the mas•s di1s1s•olved iby addition of .d:Hute sulprhU11'1i1c add to :neutrailiity. The traces of ·s•eipairalted ~ocliin.e were reduced with s1ome drops oif a suilphur -Oiio.:xiid'e soilrttiHion. The ~odi1rne· was then determined iodometriically by the method described by Viebeck and Becher10). FOIUn<l Hg 66.05% I 27.60°/o Reqiuii;ed for HgaP2I2 Hg 65. 58°/~ I 27.66°/o Phosphorus can. also he ·determi.ine:d itn the content of the .test t111he bwt in thii·s caise the 1sepa~a1tiion 01f the si1l~o~c acid from the glwss wou!Ld be neces-sary. Therefore for the phosiphoras determitn:aition the reaction was carried oUJt in a n!iid~eil crucible alilid' tlhe phosphoric acid determlilned as Mg2P 201 by the UJs:ua:I method. Foiunid RequciJred for HgsP2,I2 p 6.160/o p 6.76% 4) Preparation o.f Hg3P2I2 from the phosphorus triiodide. 2 1g• Oif phos-p!hOII'UIS tri~ocLicLe and 8 g of mercury was seaJled m a· .glaiss t111be amid heated for 15 houirs iin the mrurme:r descriibed aibove. The results of the chemica1I amaily1s1is foir the mercury amid iiiodine wer;e pr,aictiicalily the sam.e as, for the product prepared from di.iphosphoms· tefra.fodide. The X-ray phofo1g["aiphs were taikein ~n the Physka1I I.nstiturte (Faculty of Sciie:noe) by klin:d permissiilorn of iiits Di1rector Pr:ofes1s0ir M. Pai~c. LABORATORY FOR GENERAL AND INORGANIC CHEMISTRY FACULTY OJ< SU<EiNCE and MINERALOGICAL AND PETROiLOGICAL INSTITUTE . FACULTY OF SOiiENCE ZAGREB, CROATIA [Receiived, A'Pril 16, 1952] S) See F. P . . alIIJd W. D. T re <lJ .d we 11, Kmzes LehI'huch d er o.naJytischen Chem;e, II, Wien 1943, ip. 138. . 9) H. M ·eye .r, Die Ana1y,se und Ko.nstitut~onserm~ttlu.rug de1r o!l"ganischen Ver-bindunge:n, Leiipziig 1931, .p . 125. · 10) See F. iP ire ig 1 and H. Roth, Qualilltiitative oir,ga1I1d1S1ohe Md~ma:nrulyse, W:i:en 1947, p. 139. MERCURY PHOSPHOIOD-II>E 65 IZVOD 0 zivinom fosfojodidu HgaP%J% D. GRDENIC, S. SCA VNICAR i M. KESLER Gram.ger1l je opisao priredi~anj,e ii S1Voj1S·tva fivin.og fosfala Hg3P 4 • Mi smo. pono--vili Gtrainger-ove pdkuse i .dotbili kristaJi,zfra.!ll produlct: ii.stiih SIV'ojstaiva, no saistaiv mu je odgava:raio formuJli: HgsP2J2. Spoj,, koj1 bi sllldr'ZlW&O saimo fosfor i z.Dviu, niSIIIlO mog1i dobiitri rp:omo'6u opcrsane metode. Krista1L~ 1su monoilcliinski i pripadaJju p1'ostorno1j gru!p'i C~h - P21/c. Element.a.ma stlllilica Slaldr<Zi 12 stehiomet.fij&kLh jediill:ica HgsP2J2 ii. njene su dimenzii!je: a~ 13,07 A b = 12,44 A c = 17,16 A B = 102,2° Dajemo op·is metode p•riir··edivamja., te kriistl!Jlog1raifske j, .kem:ijske podaitke. U piri-piremci. je ii&traZiiivanje k!!~stai!ne 1strukture rnntgemogirafskim meto·daima .. Rentgenski snimci ucmjeni SU '11 fiz"ckom ins•titutJu p·rkodoslovno-matemaitskQg ·failrultetei =etlji;vOISOu upraivi telj<a profesor.a M. Paiica. J..ABORATORU ZA OPCU I ANORGANSKU KEMIJU PRIRODOSLOVNO-MATEMATICKI FAKULTET I MINEROLOSKO-PETROLOSKI INSTITUT PRIRODOSLOVNO-MATEMATICKI F AKULTET ZAGREB :5 Arhiv za kemij-u, Primljeno 16. travnja 1952-

On the Mercury Phosphoiodide Hg3P2I2

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