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1.
Radiochemistry - A new mixed-cation complex Li2Na[NpO2(MoO4)2]·4H2O with NpO2+ : MoO42– = 1 : 2 has been synthesized and structurally characterized. The coordination environment of Np(V)... 相似文献
2.
Actinide(VII) salts Rb3[NpO4(OH)2]·3H2O (I) and Rb3[PuO4(OH)2]·3H2O (II) were prepared as single crystals and examined by X-ray diffraction. The compounds are isostructural and crystallize in the monoclinic system, space group C2/c, Z = 4; unit cell parameters: a = 12.1544(3), b = 10.9942(2), c = 7.789(2) ?, ?? = 91.0930(11)° for I and a = 12.1254(3), b = 10.9506(2), c = 7.7699(2) ?, ?? = 90.8253(12)° for II. The main structural elements of I and II are centrosymmetrical anions [AnO4(OH)2]3? forming together with water molecules, owing to strong hydrogen bonding, chains oriented along [101]. In [AnO4(OH)2]3? anions, the central An(VII) atom has a tetragonal-bipyramidal oxygen surrounding. The An-O(OH) interatomic distances decrease in going from I to II owing to actinide contraction by a factor of ??2 more strongly than the An-O bond lengths in the equatorial planes of the bipyramids. The previously studied structure of Cs3[NpO4(OH)2]·3H2O (III) was refined. 相似文献
3.
A new oxalate complex, Na4(NpO2)2(C2O4)3·6H2O, with the Np:C2O4 ratio of 2:3 was synthesized and studied by single crystal X-ray diffraction. In the crystal, the NpO 2 + cations and oxalate anions are bound in open networks [(NpO2)2(C2O4)3] n 4n- parallel to the bc plane. The Na(1) cations are accommodated in large voids of the neptunyl oxalate networks with the formation of crimped mixed-cation layers of the composition [Na2(NpO2)2(C2O4)3] n 2n- . The negative charge of the layers is compensated by the Na(2) cations arranged between the layers. The Np atoms have a pentagonal bipyramidal coordination surrounding with the equatorial plane formed by the oxygen atoms of three oxalate anions. The structure contains tridentate-bridging and tetradentate-bridging oxalate anions. 相似文献
4.
A new mixed-valent Np(IV)/Np(V) chloride, [Np(NpO2)6(H2O)8(OH)Cl9]·H2O, was synthesized, and its crystal structure was determined. The crystals consist of NpO 2 + and Np4+ cations, of Cl? and OH? anions, of coordination-bonded water molecules, and of water molecules of crystallization. The Np(V) atom, Np(1), has pentagonal bipyramidal coordination surrounding with O atoms in the apical position and with the equatorial plane formed by three Cl? anions, O atom of the adjacent NpO 2 + cation, and O atom of water molecule. The mutual coordination of the neptunyl(V) ions, cation-cation (CC) interaction, links the Np(1) coordination polyhedra via common vertices into rings around sixfold axes, with the Np(V)?Np(V) distance in these fragments of 4.276 Å. The ring fragments are linked with each other via common equatorial edges of the bipyramids into layers perpendicular to c-axis. The Np(IV) atom, Np(2), has coordination surrounding in the form of tricapped trigonal prism (CN 9) with the tetragonal lateral faces formed by the O atoms of the NpO 2 + cations and the capping positions occupied by the O atoms of two water molecules and one hydroxy group. The Np(2) atoms act in CC interactions as coordination center for six NpO 2 + ions, with the Np(IV)?Np(V) distance of 4.183 Å. The Np(2) polyhedra are arranged in the crystal between layers of the Np(1) coordination polyhedra, linking them with each other. 相似文献
5.
《晶体工程》2000,3(4):237-250
Two novel materials, [HMTA-H··H2O] [HMTA-CH2OH] [H3V10O28[Na(H2O)4}]·4H2O, 1 and [Na2(H2O)10][H3V10O28[Na(H2O)2}]·3H2O, 2 containing decavanadate clusters interconnected through hydrated sodium cations forming 1D molecular chains and 2D molecular arrays have been self-assembled from acidified, aqueous vanadate solution in the presence of organic bases, hexamethylenetetramine and 1,3,5-triazine respectively. 相似文献
6.
《Materials Research Bulletin》1987,22(11):1483-1491
Single crystal of [Y(H2O)3]2 (C6Br2O4)3·6H2O and [Y(H2O)3]2 (C6Cl2O4)3·6.6H2O were grown in aqueous silicagel. The compounds are in principle isostructural. In Y chloranilate one additional water site is occupied as verified by X-ray single crystal structure analysis. Y3+ is nine-coordinated by three water molecules and six oxygen atoms of the bischelating (C6X2O4)2− ions (XCl, Br). The coordination polyhedron is an only slightly distorted tri-capped trigonal prism. The connection of Y3+ with the dianions leads to infinite, corrugated layers. The layer stacking yields cage-like cavities in which water molecules are accomodated. Hydrogen bonds interlink adjacent layers. Further hydrogen bonds involve the entrapped water molecules. DSC measurements indicated a complicated dehydration process which caused right at the start destruction of the single crystals. 相似文献
7.
A procedure was developed for preparing aluminum hydroxouranophosphate and hydroxourano- arsenate. The structural features and thermal decomposition pathways of the compounds were studied by X-ray diffraction, IR spectroscopy, and thermal analysis. 相似文献
8.
《晶体工程》1999,2(4):251-264
The influence of concentration of water and metal salt in the reaction between Cd(NO3)2·4H2O and 4,4′–bipyridine in MeOH has been studied and three compounds namely, T-shaped [Cd(bpy)1.5(NO3)2]·3H2O, 1 square grid [Cd(bpy)2(H2O)2](NO3)2 4H2O, 2 and one dimensional linear polymer, [Cd(bpy)(H2O)2(NO3)2], 3 were isolated quantitatively in this process. Compound 1 forms in MeOH at high dilution of the metal salt (5.0 mg/mL or less) and for the metal-to-ligand ratio 1:(1.5–2.0). Compound 2 forms exclusively in the concentration range, 17–33% for water in MeOH by volume and 12–28 mg/mL for the metal salt of the solution. Outside these limits, mixtures of 2 and 3 were isolated. For 1:1 ratio of metal salt to bpy, the linear polymer, 3 was obtained in major quantity and its formation was found to be independent of concentration of water or the metal salt. Compounds 1 and 2 have been characterized by X-ray crystallography. On heating all the compounds decompose through a common intermediate [Cd(bpy)(NO3)2] and finally to CdO as monitored by TG. 相似文献
9.
The structure of NH4[(NpO2)3(C2H5COO)4(H2O)]·3H2O was studied by single crystal X-ray diffraction. The single crystals were prepared by hydrothermal synthesis. In the structure, there are three crystallographically independent Np atoms with different equatorial surrounding. All of them have CN 7; the coordination polyhedron is a distorted pentagonal bipyramid. Each NpO 2 + cation is bonded to four other cations, acting simultaneously as a bidentate ligand and a coordination center for two other dioxocations. The cation-cation interactions result in formation of trigonal-hexagonal cationic networks. 相似文献
10.
The crystal structure of (NpO2)2(OOC)2C6H4·4H2O [rhombic cell: a = 15.937(3), b = 26.922(5), c = 8.020(2) Å, space group Pbcn, Z = 8, V = 3441.0(12) Å3, d
calc = 2.988 g cm-
3, CAD4, MoK
, graphite monochromator, 2934 independent reflections; R
1 = 0.0352, wR
2 = 0.0951] was studied. The structure consists of NpO2
+ cations, H4C6(COO)2
2
- anions, and molecules of coordinated and crystallization water. The crystal lattice involves neutral layers [(NpO2)2(OOC)2C6H4(H2O)3]
n
parallel to the {101} plane. The dioxocations in these layers are bonded to each other to form cationic networks [the Np···Np distance is 3.911(1)-4.202(1) Å]. The coordination polyhedra of Np(1) and Np(2) are pentagonal bipyramids (CN 7). The point group of the neptunyl(V) groups is close to D
h. These groups are bidentate ligands in the cation-cation interaction. The Np = O bond lengths are 1.852(6) [Np(1)-O(1)], 1.849(7) [Np(1)-O(2)], 1.845(7) [Np(2)-O(3)], and 1.841(7) Å [Np(2)-O(4)]; the O = Np = O bond angles are 178.6(3)° [O(2)-Np(1)-O(1)] and 177.4(3)° [O(3)-Np(2)-O(4)]. The equatorial plane of the Np(1) bipyramid consists of two oxygen atoms of adjacent Np(2)O2
+ dioxocations, two water molecules, and a single oxygen atom of the phthalate anion. The equatorial plane of the Np(2) bipyramid consists of two oxygen atoms of adjacent Np(1)O2
+ dioxocations, two oxygen atom of the phthalate anion, and a single water molecule. The bond lengths in the equatorial plane of the bipyramid lie in the following ranges: Np-Oyl 2.373(7)-2.437(7) Å (average 2.397 Å) , Np-Ophth 2.360(7)-2.474(7) Å (average 2.431 Å), and Np-Owater 2.534(8)-2.558(9) Å (average 2.544 Å). The phthalate anions are tridentate bridging ligands binding neptunium atoms only within a single cationic network. 相似文献
11.
L. B. Serezhkina A. V. Vologzhanina M. O. Karasev V. N. Serezhkin 《Radiochemistry》2011,53(2):142-145
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) Å, 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. 相似文献
12.
Double U(VI) phthalates with NH 4 + , K+, and Cs+ ions in the outer sphere were synthesized. The X-ray phase analysis shows that their structures are similar. Single crystals were prepared and the structure of K4[(UO2)4(μ3-O)2(C6H4C2O4)4] ? 3H2O was solved. In the [(UO2)4O2(C6H4C2O4)4]4? anions forming the main structural motif, each bridging oxygen atom μ3-O combines one pentagonal and two hexagonal bipyramids, which, in turn, are combined in centrosymmetrical tetramers. The phthalate ions have coordination capacity equal to 3; each ligand coordinates U(1) in the bidentate fashion via one carboxy group and U(2) in the bidentate fashion to form a planar seven-membered chelate ring. 相似文献
13.
NaMg(H2O)2[BP2O8]·H2O was prepared by hydrothermal synthesis and was characterized by X-ray powder difraction and IR method. The title compound was synthesized from MgCl2·6H2O, NaBO3·4H2O, and (NH4)2HPO4 with variable molar ratios using hydrothermal method by heating at 165 °C for 3 days. The X-ray powder diffraction data was indexed in hexagonal system, the unit cell parameters were found to be as a = 9.428, c = 15.82 Å, Z = 4 and the space group is P6122. It is isostructural with MlMll(H2O)[BP2O8] type compounds where Ml = Na, K; Mll = Mg, Mn, Fe, Co, Ni and Zn. In addition NH4Mg(H2O)2[BP2O8]·H2O was also synthesized the first time in this research. Its unit cell parameters and hkl values were in good agreement with the sodium magnesium compound. The unit cell parameters are a = 9.529, c = 15.736 Å. The indexed X-ray powder diffraction data of both compounds which were not reported in the literature is presented in this work. The IR data of NaMg(H2O)2[BP2O8]·H2O is also reported. 相似文献
14.
《Materials Chemistry and Physics》1986,14(3):209-217
The thermal decomposition of synthetic [Ni2Al(OH)6]2SO4· nH2O in air has been studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption. A very drastic decreasing of the specific surface area is observed after total dehydration (345°C) of the original sample. However, the specific surface area highly increases when the sample is treated at 640°C, decreasing again at 1000°C. No microporosity was found in the range of temperature studied. However, slit-shaped and cylindrical mesopores were observed in 640°C and 1000°C treated samples, respectively. 相似文献
15.
《Materials Science & Technology》2013,29(8):968-974
AbstractThe influence of long term soft milling of a mixture of (1) Mg(OH)2 and α-Fe2O3 and (2) Mg(OH)2 and Fe(OH)3 powders in a planetary ball mill on the reaction synthesis of nanosized MgFe2O4 ferrites was studied. Soft mechanochemical reaction leading to formation of the MgFe2O4 spinel phase was followed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and magnetisation measurements. The spinel phase formation was first observed after 5 h of milling and its formation was completed after 15 h in case (2). The synthesised MgFe2O4 ferrite had a nanocrystalline structure with a crystallite size of about 10 and 15 nm respectively for cases (1) and (2). Measurements after 15 h of milling show magnetisation values of 15·23 and 10·14 J T–1 kg–1 respectively for cases (1) and (2). 相似文献
16.
L. B. Serezhkina A. V. Vologzhanina A. G. Verevkin V. N. Serezhkin 《Radiochemistry》2011,53(4):354-357
An X-ray diffraction study of Rb[UO2(SeO4)F]·H2O (I) was performed. The compound crystallizes in the rhombic system with the following unit cell parameters: a = 8.4753(6), b = 13.5234(9), c = 13.5296(9) Å, space group Pnma, Z = 8, V = 1550.7(2) Å3; R = 0.0248. The principal structural units of crystals of I are [UO2(SeO4)F]? layers belonging to crystal-chemical group AT3M2 (A = UO 2 2+ , T3 = SeO 4 2? , M2 = F?) of uranyl complexes. The uranium-containing layered units are combined via electrostatic interaction with Rb cations and via a system of hydrogen bonds involving outer-sphere water molecules. 相似文献
17.
The structure of new mixed-valent An(IV)/Np(V) compounds [An(NpO2)(H2O)3(CBr3COO)5]·CBr3COOH·nH2O, where An(IV) = Th and Np, was studied. Two independent Np(V) atoms have the coordination surrounding in the form of pentagonal bipyramids with the O atoms of NpO 2 + dioxocations in apical positions; the equatorial planes of the bipyramids are constituted by the O atoms of five CBr3COO? ions. Two independent An(IV) atoms have the oxygen surrounding in the form of distorted tricapped trigonal prisms (CN = 9) constituted by the O atoms of four CBr3COO? ions, two NpO 2 + cations, and three water molecules. Eight of ten independent CBr3COO? anions link the An4+ and NpO 2 + cations in the bidentate bridging fashion into electrically neutral chains [An(NpO2)(H2O)3(CBr3COO)5]n, and two CBr3COO? anions interact with two independent NpO 2 + dioxocations in the monodentate fashion. CBr3COOH and water molecules are located between the layers. In the [An(NpO2)(H2O)3(CBr3COO)5]n chains, NpO 2 + cations alternate with An4+ cations, and mixed-valent An(IV)/Np(V) cation-cation interaction arises, in which each NpO 2 + cation acts as a bidentate ligand and An4+ acts as coordination center for two dioxocations. [Th(NpO2)(H2O)3(CBr3COO)5]·CBr3COOH·2H2O is the first example of a Th(IV) compound in which cation-cation bonds with the NpO 2 + ions are present. 相似文献
18.
K[(NpO2)(SiO3OH)]·H2O (I) and K[(PuO2)(SiO3OH)]·H2O (II) were prepared by hydrothermal synthesis at 120°C, and their IR and near-IR spectra were measured. The unit cell parameters of the compounds were determined from powder X-ray patterns [a = 7.068(1), b = 7.064(2), c = 6.640(1) Å. = 106.68(1)°, V = 317.6 Å3 (I); a = 7.102(1), b = 7.100(2), c = 6.637(1) Å, = 107.62(1)°, V = 318.9 Å3 (II)]. These compounds are isostructural with potassium boltwoodite K[(UO2)(SiO3OH)]·H2O. 相似文献
19.
《Zeolites》1995,15(6):561-568
The halate sodalites of the compositions Na8[AlSiO4]6(ClO3)1.91(OH)0.09 and Na8[AlSiO4]6(BrO3)1.77(OH)0.23 have been prepared using low-temperature solution syntheses and the derivatives Na4.7Li3.3[AlSiO4]6(ClO3)1.91(OH)0.09, Na3.3K4.7[AlSiO4]6(ClO3)1.91(OH)0.09, Na3.3Li4.7[AlSiO4]6(BrO3)1.77(OH)0.23, and Na3.3K4.7[AlSiO4]6(BrO3)1.77(OH)0.23 obtained by aqueous cation exchange. All products crystallize with the cubic sodalite structure in the space group P43n. Rietveld profile refinement has been completed from powder neutron diffraction data collected at 4 and 300 K revealing a structure similar to that found for perchlorate sodalite, with the anion positioned slightly off the cage center. Infrared and Raman spectroscopy has verified the presence of the halate anions within the β-cage, and29SiMAS n.m.r. has confirmed that the framework ordering is consistent with the space group. Thermogravimetric analyses have provided information on the extent of halate entrapment, stability within the cage, and decomposition properties. 相似文献
20.
A. V. Savchenkov A. V. Vologzhanina L. B. Serezhkina D. V. Pushkin V. N. Serezhkin 《Radiochemistry》2013,55(5):466-471
Synthesis and the results of IR and single crystal X-ray diffraction study of Na4(UO2)4(i-C4H9COO)11·(NO3)·3H2O are reported. The crystals are monoclinic; the unit cell parameters at 100 K are as follows: a = 13.697(2), b = 20.285(3), c = 15.991(3) Å, β = 103.760(3)°, space group P21, Z = 2, R = 0.0650. The uraniumcontaining structural units are mononuclear moieties [UO2(i-C4H9COO)3]? and [UO2(NO3)(i-C4H9COO)2]?, belonging to crystal-chemical group AB 3 01 (A = UO 2 2+ , B01 = i-C4H9COO? and NO 3 ? ) of uranyl complexes. The IR data are consistent with the results of the single crystal X-ray diffraction study. The influence of the carboxylate ligand volume on the structure of Na[UO2L3]·nH2O crystals (L = acetate, n-butyrate, isovalerate ion) is analyzed. 相似文献