Structural Units Of Crystals Research Articles

Lithium, sodium and strontium fluoroglutaratouranylates: structure and some properties

Using X-ray diffraction analysis, the structure of the crystals of Li(UO2)2(C5H6O4)2F⋅6H2O (I), NaUO2(C5H6O4)F⋅4H2O (II) and Sr(UO2)2(C5H6O4)2F2⋅8H2O (III) was studied for the first time. The uranium-containing structural units in crystals of I are 1D complexes [UO2(C5H6O4)F0.5(H2O)]0.5– with the crystal chemical formula AQ02M20.5M1, where A = UO22+, Q02 = C5H6O42–, M2= F–, M1 = H2O, and in II and III, 1D complexes of the same composition and structure [UO2(C5H6O4)F]– with the crystal chemical formula AQ02M2. In all compounds, the U(VI) atoms implement hexagonal-bipyramidal coordination, forming coordination polyhedra UO2FO5 (I) and UO2F2O4 (II and III). It was found that the long-characterized uranyl fluoroglutarate {UJUBEG}, for which the composition [UO2(С5H6O4)F]⋅2H2O was erroneously indicated, contradicting the principle of electrical neutrality, should be considered as (Н3O)[UO2(С5H6O4)F]⋅H2O.

Energetic Co-Crystal of a Primary Metal-Free Explosive with BTF. Ideal Pair for Co-Crystallization.

Co-crystallization is an elegant technique to tune the physical properties of crystalline solids. In the field of energetic materials, co-crystallization is currently playing an important role in the engineering of crystals with improved performance. Here, based on an analysis of the structural features of the green primary explosive, tetramethylammonium salt of 7-oxo-5-(trinitromethyl)-4,5,6,7-tetrahydrotetrazolo[1,5-a][1,3,5]triazin-5-ide (1), a co-former such as the powerful secondary explosive, benzotrifuroxan (BTF, 2), has been proposed to improve it. Compared to the original 1, its co-crystal with BTF has a higher detonation pressure and velocity, as well as an initiating ability, while the impact sensitivity and thermal stability remained at about the same level. Both co-formers, 1 and 2, and co-crystal 3 were characterized by single-crystal X-ray diffraction and their crystal packing was analyzed in detail by the set of approaches, including periodic calculations. In the co-crystal 3, all intermolecular interactions were significantly redistributed. However, no new types of intermolecular interactions were formed during co-crystallization. Moreover, the interaction energies of structural units in crystals before and after co-crystallization were approximately the same. A similar trend was observed for the volumes occupied by structural units and their densifications. The similar nature of the organization of the crystals of the co-formers and the co-crystal gives grounds to assert that the selected co-formers are an ideal pair for co-crystallization, and the invariability of the organization of the crystals was probably responsible for the preservation of some of their properties.

Synthesis, Crystal Structure, and Molecular Structure of Maleate Tris(Benzohydrazide) Cobalt(II) Tetrahydrate [Co(L1)3](Mal) · 4H2O and Maleate Tris(Phenylacethydrazide) Nikel(II) Monohydrate [Ni(L2)3](Mal) · H2O

Coordination compounds [Co(L1)3](Mal) · 4H2O (I) and [Ni(L2)3](Mal) · H2O (II) (L1 is benzohydrazide, L2 is phenylacethydrazide, and H2Mal is maleic acid) have been synthesized and characterized by IR spectroscopy and diffuse reflectance spectroscopy. Crystal structures of I and II have been determined by single-crystal X-ray diffraction. Structural units of crystals I and II are complex cations [Co(L1)3]2+ and [Ni(L2)3]2+, respectively, maleate-ions Mal2–, and crystallized water molecules bound by a branched system of hydrogen bonds. Metal atoms at the complex cations of crystals I and II have octahedral coordination (3O + 3N) formed by three bidentate chelate ligands Ln (n = 1, 2).

Synthesis and Structure of U(VI), Np(VI), and Pu(VI) Phenylacetates

Phenylacetates [AnO2(C6H5CH2COO)2], where An = U (I), Np (II), or Pu (III), were synthesized and studied by single crystal X-ray diffraction. Compounds I–III are isostructural and crystallize in the monoclinic system, space group C2/c, Z = 4. The main structural units in crystals of I–III are 1D chains [AnO2·(C6H5CH2COO)2] belonging to crystal-chemical group $${\rm{AB}}_2^{11}$$ ( $${\rm{A}} = {\rm{AnO}}_2^{2 + }$$ , B11 = C6H5CH2COO−). The intermolecular interactions in the structures of [AnO2L2] crystals, where L is benzoate or phenylacetate ion, were analyzed by the method of molecular Voronoi-Dirichlet polyhedra. The X-ray structural data were confirmed by analysis of the IR and electronic absorption spectra.

Synthesis, Crystal, and Molecular Structure of bis(Thiosemicarbazide)Nickel(II) 1,5-Naphthalene Disulfonate Dihydrate Complex [Ni(Tsc)2](1,5-Nds) · 2H2O

Complex [Ni(Tsc)2](1.5-Nds) · 2H2O (I), where Tsc = thiosemicarbazide, NH2NHC(=S)NH2; 1,5-Nds2– is double deprotonated anion of 1,5-naphthalene disulfonic acid $$\rm{CH_{10}H_6(SO_3)_2^{2-}}$$ was synthesized, characterized by IR spectroscopy, and studied by thermogravimetry and X-ray diffraction. Crystal I is built of complex cations [Ni(Tsc)2]2+, anions (Nds)2–, and crystallization water molecules. The Ni atom is coordinated along the vertices of the trans-square by two sulfur atoms and two nitrogen atoms of two bidentate chelating ligands Tsc. The structural units of crystal I are joined by a branched network of N–H···O and O–H···O hydrogen bonds with the participation of donors, namely, the hydrogen atoms of two NH2 groups and the NH group of complex cation [Cu(Tsc)]2+ and the H atoms of water molecules, and acceptors, namely, oxygen atoms of the sulfate group of anion 1,5-Nds2– and solvate water molecules.

Synthesis, Crystal, and Molecular Structure of Bis(thiosemicarbazide)zinc(II) 1,5-Naphthalenedisulfonate Monohydrate [Zn(Tsc)2](1,5-Nds) · H2O

Complex [Zn(Tsc)2](Nds) · H2O (I) (Tsc is thiosemicarbazide, NH2NHC(=S)NH2, and 1,5-Nds2–is the double-deprotonated anion of 1,5-naphthalenedisulfonic acid, C10H6(SO3) 2 2- ) has been synthesized and studied by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The structural units of crystal I are complex cations [Zn(Tsc)2]2+, anions (Nds)2–, and crystallization water molecules. The Zn atom is coordinated along the vertices of the distorted tetrahedron by two sulfur atoms and two nitrogen atoms of two bidentate chelate (S,N) Tsc ligands. The structural units of crystal I are joined together by a branched network of the N–H···O hydrogen bonds involving independent donor hydrogen atoms of the NH2 and NH groups of Tsc molecules (nine of ten, except for the H(6A) atom), all six independent acceptor oxygen atoms of the SO3 groups of the Nds2– anions, and two acceptor hydrogen atoms and one donor oxygen atom of the water molecule.

Synthesis and X-ray diffraction study of new uranyl malonate and oxalate complexes with carbamide

Two new malonate-containing uranyl complexes with carbamide of the formulas [UO2(C3H2O4)(Urea)2] (I) and [UO2(C3H2O4)(Urea)3] (II), where Urea is carbamide, and one uranyl oxalate complex of the formula [UO2(C2O4)(Urea)3] (III) were synthesized, and their crystals were studied by X-ray diffraction. The main structural units in crystals I are the electroneutral chains [UO2(C3H2O4)(Urea)2]∞ belonging to the crystal-chemical group AT11M21 (A = UO22+, T11 = C3H2O42-, M1 = Urea) of uranyl complexes. Crystals II and III are composed of the molecular complexes [UO2(L)(Urea)3], where L = C3H2O42- or C2O42-, belonging to the crystal-chemical group AB01M31 (A = UO22+, B01 = C3H2O42- or C2O42-, M1 = Urea). The characteristic features of the packing of the uranium-containing complexes are discussed in terms of molecular Voronoi–Dirichlet polyhedra. The effect of the Urea: U ratio on the structure of uranium-containing structural units is considered.

How Can Synchrotron Radiation Techniques Be Applied for Detecting Microstructures in Amorphous Alloys?

In this work, how synchrotron radiation techniques can be applied for detecting the microstructure in metallic glass (MG) is studied. The unit cells are the basic structural units in crystals, though it has been suggested that the co-existence of various clusters may be the universal structural feature in MG. Therefore, it is a challenge to detect microstructures of MG even at the short-range scale by directly using synchrotron radiation techniques, such as X-ray diffraction and X-ray absorption methods. Here, a feasible scheme is developed where some state-of-the-art synchrotron radiation-based experiments can be combined with simulations to investigate the microstructure in MG. By studying a typical MG composition (Zr70Pd30), it is found that various clusters do co-exist in its microstructure, and icosahedral-like clusters are the popular structural units. This is the structural origin where there is precipitation of an icosahedral quasicrystalline phase prior to phase transformation from glass to crystal when heating Zr70Pd30 MG.

Synthesis and structure of cesium-containing zippeite

Synthetic zippeite Cs3[(UO2)4(SO4)2O3(OH)]·3H2O (I) was prepared, its IR spectra were examined, and single crystal X-ray diffraction analysis was performed. The compound crystallizes in the triclinic system with the unit cell parameters a = 8.7833(5), b = 9.5871(6), s = 13.7925(8) A, α = 83.518(4)°, β = 71.619(4)°, γ = 89.664(4)°, space group \(P\bar 1\), Z = 2. The uranium-containing structural units in crystals of I are layers of the composition [(UO2)4(SO4)2O3(OH)]3−, belonging to crystal-chemical group A4Q 2 4 M 4 3 (A = UO 2 2+ , Q4 = SO 4 2− , M3 = O2− and OH−) of uranyl complexes. The characteristics of the Voronoi-Dirichlet polyhedra of the oxygen atoms allow the O atoms of M3 ligands (OH− and O2−) in the structures of U(VI) minerals to be distinguished without available data on the positions of hydrogen atoms.

Synthesis and structure of R 2[UO2(NO3)2(NCS)2] (R = Rb or Cs)

Crystals Rb2[UO2(NO3)2(NCS)2] (I) and Cs2[UO2(NO3)2(NCS)2] (II) have been synthesized and studied by IR spectroscopy and X-ray diffraction. Crystals I are monoclinic, with the following parameters: a = 12.2118(5) A, b = 10.2545(3) A, c = 11.8754(4) A, β = 110.287(1)°, sp. gr. C2/c, Z = 4, and R = 0.0523. Crystals II are orthorhombic, with a = 13.7309(3) A, b = 10.5749(2) A, c = 10.1891(2) A, sp. gr. Pnma, Z = 4, and R = 0.0411. The basic structural units of crystals I and II are one-core complexes [UO2(NO3)2(NCS)2]2−, which belong to the crystallochemical group cis-AB 2 01 M 2 1 (A = UO 2 2+ , B 01 = NO 3 − , M 1 = NCS−), which are combined into a framework via electrostatic interactions with ions of alkaline metals R (R = Rb or Cs). The structural features of crystals I and II, which condition the formation of [UO2(NO3)2(NCS)2]2− complexes with a cis rather than a trans position of isothiocyanate ions in the coordination sphere of uranyl ions, are discussed.

Crystal and molecular structure of diaquadinitratouranyl dihydrate [UO2(NO3)2(H2O)2] · 2H2O

Single crystals of previously unknown diaquadinitratouranyl dihydrate [UO2(NO3)2(H2O)2] · 2H2O (I) were obtained by evaporation of aqueous solution of [UO2(NO3)2(H2O)2] · 4H2O containing nitric acid in air at ambient temperature. The structure of the complex was studied by X-ray diffraction analysis. Crystals are monoclinic, a = 7.6820(15) A, b = 9.887(2) A, c = 7.1990(14) A, β = 105.08(3)°, space group P21/c, Z = 2, V = 527.95(18) A3. Structural units of crystal are neutral centrosymmetrical molecular complexes [UO2(NO3)2(H2O)2] and crystal water molecules united by a hydrogen bond system. Certain structural and spectral characteristics of new complex I and known diaquadinitratouranyl complexes were compared.

Structure and some properties of [UO2(SeO4)(C5H12N2O)2(H2O)

The complex [UO2(SeO4)(C5H12N2O)2(H2O)] (I) was synthesized and studied by thermal analysis, IR spectroscopy, and X-ray crystallography. The crystals are orthorhombic: a = 13.1661(3) A, b = 16.4420(5) A, c = 17.4548(6) A, Pbca, Z = 8, R = 0.0423. The structural units of crystal I are chains with the composition coinciding with that of the compounds of the AB2M31 crystal chemical group of the uranyl complexes (A = UO22+, B2 = SeO42−, M1 = C5H12N2O and H2O).

Synthesis and structure of Cs3[UO2(CH3COO)3]2(NCS)·H2O

The compound Cs3[UO2(CH3COO)3]2(NCS)·H2O (I) was synthesized and studied by IR spectroscopy and single crystal X-ray diffraction. Compound I crystallizes in the monoclinic system with the following unit cell parameters: a = 7.8286(9), b = 19.892(2), c = 20.050(2) A, β = 94.527(2)°, space group P21/c, Z = 4, R = 0.0387. The uranium-containing structural units in crystals of I are mononuclear complexes [UO2(CH3COO)3]− belonging to crystal-chemical group AB 3 01 (A = UO 2 2+ , B01 = CH3COO−) of uranyl complexes.

A restudy of the crystal structure of tetraaquastrontium dicitratoborate trihydrate

The crystal structure of Sr(H2O)4[(C12H11O14)B] · 3H2O (I) has been restudied and determined with a higher accuracy. The crystals are monoclinic, space group P21/n, a = 11.405(1) A, b = 18.814(1) A, c = 11.987(1) A, β = 110.79(1)°; Z = 4. The structure was refined by full matrix least-squares calculation to R = 0.0547 on 5343 unique reflections with R int = 0.0419. The structural units of crystal I are the Sr2+ cation, seven water molecules, and doubly charged dicitratoborate anion, which is not equivalent to the singly charged complex dicitratoborate anion identified previously in the crystal structures of complexes of boric and citric acids. The coordination polyhedron of the Sr2+ cation is a distorted dodecahedron composed of four O atoms of coordinated water molecules and four O atoms of two complex anions. The crystal packing of I is layered. Thirteen independent O-H…O and O-H…, O′ contacts form an intricate system of hydrogen bonds.

Synthesis and structure of (NH4)3[UO2(CH3COO)3]2(NCS)

The compound (NH4)3[UO2(CH3COO)3]2(NCS) (I) was synthesized and examined by single crystal X-ray diffraction analysis. The compound crystallizes in the rhombic system with the unit cell parameters a = 11.5546(4), b = 18.5548(7), c = 6.7222(3) A, V = 1441.19(10) A3, space group P21212, Z = 2, R = 0.0345. The uranium-containing structural units of crystals of I are isolated mononuclear groups [UO2(CH3COO)3]− belonging to crystal-chemical group AB 3 01 (A = UO 2 2+ , B01 = CH3COO−) of uranyl complexes. The specific features of packing of the uranium-containing complexes in the crystal structure are considered.

Synthesis and crystal structure of (NH4)3[UO2(CH3COO)3]2[UO2(CH3COO)(NCS)2(H2O)

Single crystals of the compound (NH4)3[UO2(CH3COO)3]2[UO2(CH3COO)(NCS)2(H2O)] (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 18.3414(6) A, b = 16.3858(7) A, c = 12.4183(5) A, β = 92.992(1)°, space group C2/c, Z = 4, V = 3727.1(3) A3, and R = 0.0253. The uranium-containing structural units of crystals I are mononuclear complexes of two types with an island structure, i.e., the [UO2(CH3COO)3]− anionic complexes belonging to the crystal-chemical group (AB301 = UO22+, B01 = CH3COO−) of the uranyl complexes and the [UO2(CH3COO)(NCS)2(H2O)]− anionic complexes belonging to the crystal-chemical group AB01M31 (A = UO22+, B01 = CH3COO−, M1 = NCS− or H2O).

Synthesis and crystal structure of Fe(III) and Al(III) complexes with 2-diphenylacetyl-1,3-indandione

Iron(III) and aluminum(III) complexes with 2-diphenylacetyl-1,3-indandione (HL) have been synthesized. The structures of the obtained compounds FeL3(I) and AlL3(II) were studied. The isostructural crystals are monoclinic, I: Z = 8, space group P21/c, a = 16.061(3) A, b = 16.658(3) A, c = 22.015(4) A, β = 111.41(3)°; II: Z = 8, space group P21/c, a = 16.115(14) A, b = 16.476(8) A, c = 21.949(20) A, β = 111.04(11)°. The structural units of crystals I and II are neutral molecules in which each ligand is bidentately coordinated to a central metal atom through the oxygen atom of the acyl keto group and an oxygen atom of the indandione fragment to form a six-membered chelate ring. In the crystals, neutral molecules I and II form pseudodimers due to stacking of indandione moieties of two adjacent coordination spheres and additional C-H…O contacts. Each pseudodimer is in contact with six neighboring dimers also through hydrogen bonds C-H…O to form an infinite framework.

Synthesis and X-ray structural investigation of (C3N6H7)4(CN3H6)2[UO2(CrO4)4] · 4H2O and (H3O)6[UO2(CrO4)4

Single crystals of the compounds (C3N6 H7)4(CN3H6)2[UO2(CrO4)4] · 4H2O (I) and (H3O)6[UO2(CrO4)4] (II) are synthesized, and their structures are investigated using X-ray diffraction. Compound I crystallizes in the triclinic system with the unit cell parameters a = 6.3951(8) A, b = 10.8187(16) A, c = 16.9709(18) A, α = 93.674(4)°, β = 97.127(4)°, γ = 92.020(4)°, space group, P\( \bar 1 \)Z = 1, V = 1161.6(3) A3, and R = 0.0470. Crystals of compound II belong to the monoclinic system with the unit cell parameters a = 14.3158(4) A, b = 11.7477(3) A, c = 13.1351(4) A, β= 105.836(1)°, space group C2/c, Z = 4, V = 2125.2(1) A3, and R = 0.0213. The uranium-containing structural units of crystals I and II are mononuclear anionic complexes of the composition [UO2(CrO4)4]6− with an island structure, which belong to the crystal-chemical group Am14 (A = UO2+2, M1 = CrO2−4) of the uranyl complexes. The [UO2(CrO4)4]6− anionic complexes are joined into a three-dimensional framework through the electrostatic interactions with outer-sphere cations and a system of hydrogen bonds.

Synthesis and structure of {NH2(C2H5)2}2[(UO2)2(C2O4)(CH3COO)4] · 2H2O

Single crystals of the compound {NH2(C2H5)2}2[(UO2)2C2O4(CH3COO)4] · 2H2O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 9.210(2) A, b = 14.321(3) A, c = 12.659(3) A, β = 105.465(13)°, V = 1609.2(6) A3, space group P21/c, Z = 2, and R = 0.0198. The structural units of crystals I are binuclear groups of the composition [(UO2)2C2O4(CH3COO)4]2− with an island structure, which belong to the crystal-chemical group A2K02B401 (A = UO22+, K02 = C2O42−, B01 = CH3COO−) of the uranyl complexes, diethylammonium cations, and water molecules. The uranium-containing groups are joined into a three-dimensional framework through electrostatic interactions with diethylammonium cations and a system of hydrogen bonds, which are formed with the participation of the atoms involved in the composition of the water molecules, oxalate ions, acetate ions, and diethylammonium cations.

Synthesis and X-ray structural investigation of K8[(UO2)2(C2O4)2(SeO4)4] · 2H2O

Single crystals of the compound K8[(UO2)2(C2O4)2(SeO4)4] · 2H2O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 14.9290(4) A, b = 7.2800(2) A, c = 15.3165(4) A, β = 109.188(1)°, V = 1572.17(7) A3, space group P21/n, Z = 2, and R = 0.0297. The uranium-containing structural units of crystals I are dimers of the composition [(UO 2)2(C2O4)2(SeO4)4]8−, which belong to the crystal-chemical group AB 01 B 2 M 1 (A = UO 2 2+ , B 01 = C2O 4 2− , B 2 = SeO 4 2− , M 1 = SeO 4 2− ) of the uranyl complexes. The [(UO2)2(C2O4)2(SeO4)4]8− dimers are joined into a three-dimensional framework through electrostatic interactions with the outer-sphere potassium cations.