cz TWELFTH EUROPEAN CRYSTALLOGRAPHY MEETING COLLECTED ABSTRACTS Vol. 2 MOSCOW, USSR, AUGUST 20—29, 1989 USSR Academy of Sciences TWELFTH EUROPEAN CRYSTALLOGRAPHIC MEETING Moscow, USSR August 20-29, 1989 COLLECTED ABSTRACTS Vol.2 The meeting is arranged by the Soviet National Committee of Cryst.allographers and the Institute of Crystallography of the USSR Academy of Sciences on behalf of the European Crystallographic Committee under the auspices of the USSR Academy of Sciences and the International Union of Crystallography. Moscow-198 9 Organizing Committee: Co—chairmen: B.K. Vainshtein, A.M.Prokhorov Conference secretary: EJH.Harutyunyan V.V.Davydov, V.P. Fatieva, P.P. Fedorov, N.P. Goltzova, A.G. Kocharov, Yu. A. Kostenko, EX. Lube, I.S. Lyubutin, Yu.M. L'vov, I.L.Minaeve, V.I. Ryabchenkov_, V.I. Simonov, E.V.Suvorov, D.I.Svergun, V.E.Volkov International Programme Committee: Chairman: V.I. Simonov (USSR) H.D.Bartunic (FRG), E.F.Bertaut (France), T.L. Blundell (U.K.), S. Garcia—Blanco (Spain), A.Kalman (Hungary)^K. Lukaszevicz (Poland), L.I.Man (USSR), Yu. Z.Nozik (USSR), H.Schenk (The Netherlands)fD.L.M.Viterbo (Italy) Collected Abstracts have been compiled by V.V. Klechkovskaya, L .L. Aksenova, О. V. Konovalov 3. CRYSTAL CHEMISTRY Oral presentations 1-3 - 4­ FFOH BRONZE PHASES TO BROH20IDS AND PBASOIDS ­ EXCURSION INTO SOME COMPLEX TOHGSTEH OXIDE SYSTEMS Arne MagnSli Arrhenius Laboratory, University of Stockholm, S­106 91 Stockholm, Sweden By hie X­ray diffraction studies in 1935 of the cubic sodium tungsten Ьгопгев НЙдд was able to solve the more than 100 years old problem of the chemical character of this peculiar group of substances. What he found was not a nuaber of discrete compounds but rather one phase with an extraordinarily wide region of composition NaxW03, with values of x ranging from about 1/3 to close to 1. The berthollide character is associated with the crystal structure where a variable proportion of sodium atoms occupy the interstices in an ЛеОз­ type skeleton of WOg­o^tahedra. An alternative way of lookiTiq at the structure is as perovskite type with a variable deficiency of sodium atoos (PTB|. Subsequent studies on bronzes containing alkali atoms larger than sodium revealed other types of skeletons of corner­linked WOg­octahedia. In addition to PTB­type interstices the tetragonal tungsten bronze type (TTBJ contains larger ones, situated in pentagonal tunnels or tubes (PT) formed by rings of five octahedra. Even larger are the interstices in the hexagonal tungsten bronze type IHTB) which contains six­sided tunnels formed by coupling of six octahedra. The skeletons of the bronze structures show a remarkable stability. Hot only can they accommodate a large variety of atoms to substitute *t the alkali atom positions, but substitution may also occur in the skeleton it­ self. Thus ГТВ­type phases occur in the XNbjOsF­wOj system, where Nb and F partly replace W and O, respectively. This phase, while possessing a bronze structure, lacks other characteristics of bronzes such as metallic lustre and electric conductivity and may properly be designated a bronzoid. Other types of bronze­like phases occur in systems like N^Os­WO^. Here some PTs in a TTB framework are filled with alternating metal and oxygen atoms which, to­ gether with the 0 five­rings of the tunnel, form pentagonal metal­oxygen bi­ pyramids linked by 0 apices to a spine which transforms the PT to a PC (penta­ gonal column)­ The PC is a frequently occurring structure element in transition metal oxides and fluorides. High resolution electron microscopy (HREM) and electron diffraction have been indespensible complements to X­ray diffraction techniques in studies of such materials and of those described below. Intergrowth tungsten bronzes (ITB) forming at low contents of large alkali atoms, e.ej. Cs, have been extensively studied by Kihlborg and coworkers. Their «ОД skeleton is formed by intergrowth of lamellae of НТВ and W03 struc­ tures. Both can vary in width, and crystallites of a particular sample almost invariably differ with respect to the thickness of the slabs. Such variations also abound within the crystallites. Thus there is no obvious correlation between gross composition and structure of the ITBs, and under practically attainable conditions the concepts of compound and phase los^ their meaning for these substances. The region of gross composition as a function of tempe­ rature of preparation seems to be fairly well defined, and the ensemble of ITBs thus behaves rather like a phase and may therefore be described as a phasoid. The conditions are similar in bronzoid ITBs with a pentavalent metal partially substituting for tungsten. ­ 5 ­ NEW MINERALS НТВ TBTBJLHEDBJLL AND MIXED RADICALS U.Yu.PushcharovBky. N.A.Yamnova, T.N.Nadezhina Moscow State University, Faculty of Geology, Moscow, USSB The review summarizes the results of recent structural determinations of four new minerals with original tetrahedral and mixed radicals. The structure of grumentite NafsigO.COH)]H20 contains an interrupted framework of tertiary [SiO.] tetrahedri, which ie untypical for the tetrahedral radical [ЧгоЛ. This silicate anion is one of 11 (Si,0)­tetrahedral configurations, revealed at the Chair of Crystallography of Moscow State University during the last 40 years. The structure of olinobehoite Be(OH), is composed of 3­ layered sheets of Be­tetrahedra linked by H­bonds. The common and distinctive features of 3­layered tetrahedral sheets in clinobehoite, zusmanite, Na,Si,07 and NaPrSigO.,. are discussed. New carbonate mineral Ha6BaTh(CO,)g.6H20 has hexagonal sym­ metry, space group R3 with unit cell parameters a = 14,175, с = 8,605 А, Нщ^ад ­ 0,035 for 565 reflections. A new type of isolated mixed radical composed of Th­icosahedron sharing edges with six [CO,]­triangles, is revealed in this structure. The deviation of C­atoms from the plane formed by three 0­atoms is 0,05 A. The framework mixed radical formed by Mg­octahedra and S­ tetrahedra makes the basis of the structure of new sulphate mi­ neral Mg­(S0.)2(0H) The crystals have tetragonal symmetry, space group P 4­|/amd ilth lattice dimensions a = 5,254, с = 12,971, Rgj^ao • 0,035 for 238 reflections. This mineral is a structural analogue of previously investigated synthetic crystal ME1(33S04(OH)1>33[H2O]0(67. The comparative crystal­chemical analysis of studied minerals allowed us to represent the connections between chemi­ cal compositions end their structures. ­ 6 ­ AIMMM Grat: SyntSwiiit StmcUf t, md шммг яя Nn Sptcfrescflfy 2 3 5 yjjHjr', G.A. Lager , G. Anrthausr , J.F. rschardson*. and T. Armbruster z 'Tcchniicht Universitat Berin, Ernst Router Platz 1, D­1000 Berlin 12. Dept. 3 fisohjIU. Uniy. LourtY*., Lean»»», KY 40292. U.S.A.. mstitut fik­ Gaowissen­ schaften, UramrsHIt Salzburg, A­S020 Salzba­f. Austria. *Оар<. Chemistry, s Univ. Loutsvise. Ub. (or Chemical and Mnaratofjcal frystafeo/aphy. Univ. Barn. Freiestrasse 3. СН­Э012. Barn, Switzerland. Singio crystals of almandeur garnet (Fo3Al2Si30t2) up to ~ 1 mm in size have been synthesized at 1073 К and 1.5 GPa in a piaten­cvRnder apparatus. Larfa cryslala ef this size hove not bean synthesized previously. The crystals Mora grown hydrefhermafy from an aside and re­metal mix in iron capsules for two days duration. We report the first single crystal X­ray structure refinement, NIR spectrum and crystal fiaW stebifezation anorajt (WSE) for synthetic end menibar akmndine. The X­ray work at 2M X Luntliiiied the space group Ia3d, «nth a,= 11.521 A (1), and osygen parameters X = 0 033*5 (10), Y = 0.04912 (10), and Z = 0.65306 (Ю). Selected bond kmgths in A aro SHOO) = 1.633 (1), FelD­OU) ­= 2.218 (1). FM2>­OU) • 2.36» (1) and At­Ot» ­ 1.893 (1). These vahies are vary similar to those reported for naturaiy occurring аитшняпе­­г1сп garnets /1/, /2/. Mossbauer spoclro taken on other armandine syntheses consisting of smaler cryslala have imilnauli seetttnei of 3.S9 I 0.01 mm/sec (298 Kl and 3.65 (78 K) and leeaw shifts of 1.28 ! 0.01 mm/sec 1298 K) and 1.42 1 (78 Ю for the Fa * doublet. Sight asymmetries and different Kne vrktths. In the ooualil wore observed and hence, two components could be fit to the spectra /3/. Ilowavar, the X­ray data do not Indkato the preaonce of more than one crystalegrephic dadecahodral «No and, tharsfore, a garnet symmetry tower a than Ia3d И.о. 12,31 at 2»i K. The asymmetry of the Fe * doublet in the Moasbalnv spectra could bo due to relaxation effocte. FT­MR moasuramonts were made on single crystale betwaan 10,000 and 1 3.000 cm' ta locate the ваеЮеае of throe bands rotated ta dd electronic 2 transition» ef tks t2, orbHal of Fa * In the dodocahodral site of point group symmetry D2. The bands are located at 7561, S7I3. and 4348 cm"'. This gives 1 \* 5324 cm"' and.a CFSE of 3744 cm' , assuming that the lower energy a, s 5 1 transition A­»­ B, Is ItOO cm" /4/. These values are lower than those calculated for natural abnandines /4/. Two Ifl bands were also observed at ­1 1 1 1 3«13 cm and ­ 3490 cm" (298 K) end 3617 cm" and 3595 cm" (78 K). They are interpreted aa OH~ stretching vibrations related to a small number 4 of (04H4) ~ groups substituting for the SK>4 tetrahedra in the hydrogarnel substitution. /1/ Pram* W„ Zeit. KiistjU. Щ. 333 (19711. /2/ Novak 0Л. and Slabs G.V.. Am. Mneral. 56, 791 (1971). /3/ Murad E., Wagner Г.Е.. Phys. Chom. Mineral» it 264 (1987). /4/ Burin; R.G.. й RMVYJWS in Mineraloey v.