Research subject. The crystal structure of christofschäferite-(Ce) was previously refined in terms of theP21/mlow-symmetrical space group, which allowed the local features of cationic arrangements to be determined. In this work, we set out to refine the crystal structure of christofschäferite-(Ce) in terms of theP21/ahigh-symmetrical space group based on the previously collected diffraction data. A topology-symmetrical analysis of the members of the chevkinite group with the general formula ofA4BC2D2(Si2O7)2O8was conducted.Materials and methods. A magmatic rock sample with christofschäferite-(Ce) inclusions was found in the vicinity of the Laacher See volcano, near Mendig, Eifel Mountains, Rhineland-Palatinate (Rheinland-Pfalz), Germany. The crystal structure was studied using single-crystal X-ray analysis.Results. Despite an increase in the symmetry to theP21/aspace group (in comparison with the previous data with theP21/mspace group), the main patterns of cation distribution between the octahedral and tetrahedral sites are preserved. However, due to the lover number of cationic sites, this distribution becomes more disordered. Based on a crystal chemical analysis of the crystal structures of natural and synthetic members of the chevkinite group in the framework of the OD theory, it is possible to combine them into a united OD family with the same OD groupoid.Conclusions. According to the OD theory, there are two structural OD-subgroups of the chevkinite group (chevkinite and perrierite). The crystal structure and symmetry of possible MDO-polytypes are predicted.

Методами рентгеноструктурного анализа и КР-спектроскопии были изучены два образца минералов группы лабунцовита из Хибинского (образец 1) и Ловозерского (образец 2) щелочных массивов – промежуточных членов твердого раствора цепинит-Na–«цепинит-Ba»–цепинит-K, которые характеризуются высокой степенью гидратации и низким содержанием внекаркасных катионов. Параметры моноклинных ячеек: a = 14.5086(6), b = 14.2174(6), c = 7.8712(3) Å, β = 117.119(4)°, V = 1444.09(11) Å3 (образец 1) и a = 14.2582(4), b = 13.7541(6), c = 7.7770(2) Å, β = 116.893(4)°, V = 1360.20(9) Å3 (образец 2). Кристаллохимические формулы (Z = 2): |A[Na0.84K0.6[(H2O)4]5.2]BK0.2CBa0.25D[Ca0.35Na0.15Fe0.025(H2O)]|{M1(Ti1.2Nb0.8)M2(Ti1.1Nb0.9)(O,OH)4(Si4O12)2} для образца 1 и |A[Na1.6(H2O,H3O)0.4]BK2C(Ba0.51Sr0.21)D[Mn0.3Ca0.2(H2O)](H2O)4|{M1(Ti1.94Nb0.06)M2(Ti1.88Nb0.12)(O,OH)4(Si4O12)2} для образца 2. Высокая степень гидратации образца 1 выражается в присутствии гидратных комплексов протона, а также тетраэдрических [H2O]4-ассоциатов. Для минералов группы лабунцовита характерен так называемый «блочный изоморфизм» связанные с различным распределением D-катионов. Проведенный нами анализ гетерополиэдрических МТ-каркасов в МГЛ позволил установить топологические особенности катионных сеток.

The crystal structure of a potentially new member of the eudialyte group, the Nb-deficient analogue of oneillite from Mont Saint-Hilaire, Québec, Canada, with the idealized formula: Na13(Ca3Mn3)Zr3(Fe,Mn)3(,Nb)(Si,Nb,) [Si3O9]2[Si9O27]2(O,OH,Cl)3•2H2O, has been re-studied within the space group P3. The unit-cell parameters are: a = 14.134(3), c = 30.178(6) Å, V = 52201 Å3. The crystal structure of the mineral has been previously investigated using the space group R3 (typical for the members of oneillite family). In this work a structural model characterized by 155 crystallographic sites was solved in the frame of the low symmetry space group P3 and refined to R = 5.9 % using 4179 reflections with F > 2(F). The cation distribution between the key sites in low symmetry is more detailed.

Термическое разложение 1,1-бис(метокси-NNO-азокси)-3-нитро-3-азабутана изучено в изотермических и неизотермических условиях. Теплоты его плавления и термического разложения равны соответственно –29.1 кДж/моль (7.0 ккал/моль) и 387 кДж/моль (92.5 ккал/моль). Проанализирован состав газообразных продуктов термического разложения. Реакция протекает автокаталитически. Реакционным центром в молекуле изученного вещества является диазеноксидная группа. Предложен механизм процесса. Лимитирующая стадия реакции включает пятичленное циклическое переходное состояние.

—The status of lazurite as a valid mineral species has been confirmed. The neotype specimen from the Malaya Bystraya gem lazurite deposit, Baikal Lake area has been studied using electron microprobe, wet chemical analysis, ESR, IR, Raman, X-ray photoelectron spectroscopy, UV-Vis-near IR absorption and luminescence spectroscopy, and powder X-ray diffraction. The empirical formula of the neotype sample is (Na 6.97 Ca 0.88 K 0.10 ) 7.96 [Si 6.04 Al 5.96 ] 12 O 24 (SO 4 ) 1.09 ( ) 0.55 Cl 0.04 ⋅0.72H 2 O, where is trisulfide radical anion, which is a blue chromophore. The idealized formula Na 7 Ca(Al 6 Si 6 O 24 )(SO 4 ) ⋅H 2 O has been approved by the IMA Commission on New Minerals, Nomenclature and Classification, proposal #20-H. The crystal structure of lazurite is characterized by commensurate and incommensurate modulations; the a parameter of the cubic sub-cell is 9.087(3) Å. The neotype sample is slightly birefringent, with α ' = 1.523(2) and γ ' = 1.525(2).

The crystal structure and crystallochemical features of a Fe-deficient zirconium-rich analog of eudialyte from the Lovozero alkaline massif (Kola peninsula) have been investigated. The unit-cell parameters of the mineral are found to be a = 14.198(1) Å, c = 30.380(1) Å, and V = 5303.9(1) Å3; sp. gr. R3m. The crystal structure is refined to the final reliability factor R = 4.2% in the anisotropic approximation of atomic displacements using 3174 reflections with F > 3σ(F). The crystallochemical formula of the mineral (Z = 3) is [Na10.38(H3O,H2O)2.79Ce0.45Sr0.4K0.2][Ca3.9Mn1.2Fe0.9][VIINa $$_{{2.13}}^{{}}$$ VZr0.87]Zr3[Si1.48Ti0.31Nb0.21][Si24O72](OH)2.9 (H2O)1.26 (Cl, S)0.94 (Roman numerals are the coordination numbers (CNs) of cations at the M2 key site). The regularities of block isomorphism in the vicinity of the M2 site in the structure of the mineral under study and related eudialyte-group minerals are discussed.

The crystal structure and crystallochemical features of a Fe-deficient zirconium-rich analog of eudialyte from the Lovozero alkaline massif (Kola peninsula) have been investigated. The unit-cell parameters of the mineral are found to be a = 14.198(1) angstrom, c = 30.380(1) angstrom, and V = 5303.9(1) angstrom(3); sp. gr. R3m. The crystal structure is refined to the final reliability factor R = 4.2% in the anisotropic approximation of atomic displacements using 3174 reflections with F > 3 sigma(F). The crystallochemical formula of the mineral (Z = 3) is [Na-10.38(H3O,H2O)(2.79)Ce0.45Sr0.4K0.2][Ca3.9Mn1.2Fe0.9][(Na2.13Zr0.87)-Na-VII-Zr-V]Zr-3[Si1.48Ti0.31Nb0.21][Si24O72](OH)(2.9) (H2O)(1.26) (Cl, S)(0.94) (Roman numerals are the coordination numbers (CNs) of cations at the M2 key site). The regularities of block isomorphism in the vicinity of the M2 site in the structure of the mineral under study and related eudialyte-group minerals are discussed.

This paper is an overview of available data on crystal structures, crystal chemical features, physical and chemical properties, and genesis of multilayer microporous compounds related to cancrinite and sodalite (CRCs). These compounds meet the criteria for considering them as zeolite-type materials and molecular sieves. Ten types of the CRCs’ frameworks (AFG, CAN, FAR, FRA, GIU, LIO, LOS, MAR, TOL, SOD) have been included into the Database of Zeolite Structures. Since the overwhelming majority of such materials are known only as phases of natural origin, a significant part of the review refers to multilayer mineral species belonging to the cancrinite group. Separate sections of the review contain data on various topological types of aluminosilicate frameworks, crystal chemistry of extra-framework components, isomorphism, IR spectroscopy, and genesis of multilayer CRCs as well as physical and chemical properties of two- and three-layer representatives of this group of microporous materials (i.e. materials with cancrinite- and sodalite-type frameworks, respectively).

A number of linkers for microchip-based (microarray) synthesis of oligonucleotides were synthesized here using photolabile intermediates. The resulting linkers are designed for covalent immobilization on slides containing both hydroxyl and amino groups. The first series of linkers was intended for the synthesis of oligonucleotide arrays for hybridization analysis. These linkers provide a strong covalent bond with the slide surface when amino groups in oligonucleotide heterocyclic bases are deprotected. The second series of linkers allows to cleave the synthesized oligonucleotides from the support on which they were synthesized. Furthermore, the use of such linkers yields oligonucleotides devoid of the phosphate group at their 3′ end. The obtained linkers were successfully tested in the synthesis of oligonucleotides on a microchip for subsequent hybridization analysis and assembly of a DNA fragment.

6 Институт геохимии и аналитической химии (ГЕОХИ) РАН, Москва Аннотация.Рассмотрены основные структурные особенности прототипов различных функциональных материалов минералов класса титаносиликатов из массивов Кольской щелочной провинции, используемых в качестве сорбентов, молекулярных сит и ионообменников, прекурсоров для дубителей, нелинейнооптических материалов и фотокатализаторов (семейство линтисита-кукисвумита, группа мурманита, каменевит, группа иванюкита, ситинакит, группа зорита, натисит, группа лабунцовита).Ионообменные и сорбционные свойства титаносиликатов обуславливают их применение для очистки жидких радиоактивных отходов с надёжной фиксацией радионуклидов