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1.
Ca(AsF3)(AsF6)2 was prepared by the reaction of CaF2 with excess AsF5 in AsF3 solvent. The compound crystallizes in an orthorhombic crystal system, space group Pnma, with a =1034.9(4) pm, b = 1001.7(4) pm and c = 1088.4(4) pm, V = 1.1283(8) nm3 and Z = 4. Calcium is coordinated to eight fluorine atoms, with six fluorine atoms located at the corners of a regular trigonal prism originating from six AsF6 units. Two rectangular faces of the trigonal prism are capped by fluorine atoms from two fluorine bridged AsF3 molecules. For the first time, AsF3 is shown to serve as a bridging ligand to two metal cations, with bridging distances of F(AsF3)-Ca = 241.1 and 243.2 pm. It was found, again for the first time, that the bridging As-F distances are shorter (172.4 and 173.1 pm) than the terminal As-F distance (184.5 pm). The Raman spectrum shows vibrational modes that are readily assigned to AsF3 and AsF6.  相似文献   

2.
In the system BaF2/BF3/PF5/anhydrous hydrogen fluoride (aHF) a compound Ba(BF4)(PF6) was isolated and characterized by Raman spectroscopy and X-ray diffraction on the single crystal. Ba(BF4)(PF6) crystallizes in a hexagonal space group with a=10.2251(4) Å, c=6.1535(4) Å, V=557.17(5) Å3 at 200 K, and Z=3. Both crystallographically independent Ba atoms possess coordination polyhedra in the shape of tri-capped trigonal prisms, which include F atoms from BF4 and PF6 anions. In the analogous system with AsF5 instead of PF5 the compound Ba(BF4)(AsF6) was isolated and characterized. It crystallizes in an orthorhombic Pnma space group with a=10.415(2) Å, b=6.325(3) Å, c=11.8297(17) Å, V=779.3(4) Å3 at 200 K, and Z=4. The coordination around Ba atom is in the shape of slightly distorted tri-capped trigonal prism which includes five F atoms from AsF6 and four F atoms from BF4 anions. When the system BaF2/BF3/AsF5/aHF is made basic with an extra addition of BaF2, the compound Ba2(BF4)2(AsF6)(H3F4) was obtained. It crystallizes in a hexagonal P63/mmc space group with a=6.8709(9) Å, c=17.327(8) Å, V=708.4(4) Å3 at 200 K, and Z=2. The barium environment in the shape of tetra-capped distorted trigonal prism involves 10 F atoms from four BF4, three AsF6 and three H3F4 anions. All F atoms, except the central atom in H3F4 moiety, act as μ2-bridges yielding a complex 3-D structural network.  相似文献   

3.
Three new compounds Ca(HF2)2, Ba4F4(HF2)(PF6)3 and Pb2F2(HF2)(PF6) were obtained in the system metal(II) fluoride and anhydrous HF (aHF) acidified with excessive PF5. The obtained polymeric solids are slightly soluble in aHF and they crystallize out of their aHF solutions. Ca(HF2)2 was prepared by simply dissolving CaF2 in a neutral aHF. It represents the second known compound with homoleptic HF environment of the central atom besides Ba(H3F4)2. The compounds Ba4F4(HF2)(PF6)3 and Pb2F2(HF2)(PF6) represent two additional examples of the formation of a polymeric zigzag ladder or ribbon composed of metal cation and fluoride anion (MF+)n besides PbF(AsF6), the first isolated compound with such zigzag ladder. The obtained new compounds were characterized by X-ray single crystal diffraction method and partly by Raman spectroscopy. Ba4F4(HF2)(PF6)3 crystallizes in a triclinic space group P1¯ with a=4.5870(2) Å, b=8.8327(3) Å, c=11.2489(3) Å, α=67.758(9)°, β=84.722(12), γ=78.283(12)°, V=413.00(3) Å3 at 200 K, Z=1 and R=0.0588. Pb2F2(HF2)(PF6) at 200 K: space group P1¯, a=4.5722(19) Å, b=4.763(2) Å, c=8.818(4) Å, α=86.967(10)°, β=76.774(10)°, γ=83.230(12)°, V=185.55(14) Å3, Z=1 and R=0.0937. Pb2F2(HF2)(PF6) at 293 K: space group P1¯, a=4.586(2) Å, b=4.781(3) Å, c=8.831(5) Å, α=87.106(13)°, β=76.830(13)°, γ=83.531(11)°, V=187.27(18) Å3, Z=1 and R=0.072. Ca(HF2)2 crystallizes in an orthorhombic Fddd space group with a=5.5709(6) Å, b=10.1111(9) Å, c=10.5945(10) Å, V=596.77(10) Å3 at 200 K, Z=8 and R=0.028.  相似文献   

4.
Eight binary salts that pair triazolium(1+), imidazolium(1+), pyrimidinium(1+), or purinium(1+) cations with the icosahedral closo-dodecafluorododecaborate(2−) anion (B12F122−) were synthesized using open-air benchtop metathesis reactions in water or acetonitrile. The scale of the reactions varied from just milligrams to nearly one gram of the K2B12F12 starting material. Other reaction conditions, the scope of the reaction, and the solubilities for the new salts are discussed. Five [heterocyclium]2[B12F12] salts, which were obtained in yields ranging from 84% to 99%, displayed significantly higher densities than the corresponding previously reported analogous [heterocyclium]2[B12H12] and [heterocyclium][CB11H12] salts. A ninth high-density salt consisted of B12F122− paired with a complex Ag4(triazole)84+ cation. The structures of eight of the nine new compounds were determined by single-crystal X-ray diffraction analysis. The density of five [heterocyclium]2[B12F12] salts was found to increase approximately linearly as the distance between the five-membered-ring heterocyclium(1+) cation centroids decreased. This work demonstrates additional flexibility for the rational design of ionic structures with predictable properties, which will ultimately permit the tailoring of ingredient-response behavior.  相似文献   

5.
Elimination of the arsenic (III) impurity AsF3 from anhydrous hydrogen fluoride has been demonstrated using a bench-scale apparatus (∼500 mL of HF), with a Ag(II) salt AgFAsF6 as a mediator. In this process, AsF3 is oxidized by AgFAsF6 to AsF5. In the next step, AsF5 is eliminated from HF by reaction with NaF. The oxidizer, AgFAsF6, is reduced to AgAsF6 which is regenerated to AgFAsF6 by F2 in HF at room temperature. This method can reduce the arsenic content in HF from a few hundred ppm to the industrially required level (<3 ppm). The results for three other methods (distillation, oxidation by F2 gas, and oxidation by K2NiF6) are reported and compared with the AgFAsF6 method in a preliminary examination (using ∼4 mL of HF).  相似文献   

6.
New compounds of the type M2(H2F3)(HF2)2(AF6) with M = Ca, A = As and M = Sr, A = As, P) were isolated. Ca2(H2F3)(HF2)2(AsF6) was prepared from Ca(AsF6)2 with repeated additions of neutral anhydrous hydrogen fluoride (aHF). It crystallizes in a space group P4322 with a = 714.67(10) pm, c = 1754.8(3) pm, V = 0.8963(2) nm3 and Z = 4. Sr2(H2F3)(HF2)2(AsF6) was prepared at room temperature by dissolving SrF2 in aHF acidified with AsF5 in mole ratio SrF2:AsF5 = 2:1. It crystallizes in a space group P4322 with a = 746.00(12) pm, c = 1805.1(5) pm, V = 1.0046(4) nm3 and Z = 4. Sr2(H2F3)(HF2)2(PF6) was prepared from Sr(XeF2)n(PF6)2 in neutral aHF. It crystallizes in a space group P4122 with a = 737.0(3) pm, c = 1793.7(14) pm, V = 0.9744(9) nm3 and Z = 4. The compounds M2(H2F3)(HF2)2(AF6) gradually lose HF at room temperature in a dynamic vacuum or during being powdered for recording IR spectra or X-ray powder ray diffraction patterns. All compounds are isotypical with coordination of nine fluorine atoms around a metal center forming a distorted Archimedian antiprism with one face capped. This is the first example of the compounds in which H2F3 and HF2 anions simultaneously bridge metal centers forming close packed three-dimensional network of polymeric compounds with low solubility in aHF. The HF2 anions are asymmetric with usual F?F distances of 227.3-228.5 pm. Vibrational frequency (ν1) of HF2 is close to that in NaHF2. The anion H2F3 exhibits unusually small F?F?F angle of 95.1°-97.6° most probably as a consequence of close packed structure.  相似文献   

7.
ANi(AsF6)3 (A = O2+, NO+, NH4+) compounds could be prepared by reaction between corresponding AAsF6 salts and Ni(AsF6)2. When mixtures of AF (A = Li, Na, K, Rb, Cs) and NiF2 are dissolved in aHF acidified with an excess of AsF5 the corresponding AAsF6 and Ni(AsF6)2 were formed in situ. For A = Li and Na only mixtures of AAsF6 and Ni(AsF6)2 were obtained, while for A = K, Rb and Cs, the final products were ANi(AsF6)3 (A = K-Cs) compounds contaminated with AAsF6 (A = K-Cs) and Ni(AsF6)2.ANi(AsF6)3 (A = H3O+, O2+, NO+, NH4+ and K+) compounds are structurally related to previously known H3OCo(AsF6)3. The main features of the structure of these compounds are rings of NiF6 octahedra sharing apexes with AsF6 octahedra connected into infinite tri-dimensional network. In this arrangement cavities are formed where single charged cations are placed.In O2Ni(AsF6)3 the vibrational band belonging to O2+ vibration is found at 1866 cm−1, which is according to the literature data one of the highest known values, and it is only 10 cm−1 lower than the value for free O2+.  相似文献   

8.
The reactions between Ln(AsF6)3 (Ln: lanthanide) and excess of XeF2 in anhydrous HF (aHF) as a solvent yield coordination compounds [Ln(XeF2)3](AsF6)3 or LnF3 together with Xe2F3AsF6 or mixtures of all mentioned products depending on the fluorobasicity of XeF2 and LnF3 along the series. XeF2 in a basic aHF is able to oxidize Pr3+ to Pr4+ besides Ce3+ to Ce4+ and Tb3+ to Tb4+. The tetrafluorides obtained are weaker fluorobases as XeF2 and are immediately exchanged with XeF2 yielding Xe2F3AsF6 and LnF4. The analogous reaction between Ln(BiF6)3 and XeF2 in aHF yields [Ln(XeF2)3](BiF6)3, Ln: La, Nd. Raman spectra of the compounds [Ln(XeF2)n](AF6)3 (A: As, Bi) show that no XeF+ salts are formed. The interaction of XeF2 with metal ion is covalent over the fluorine bridge. Analogous reactions of Ln(AsF6)3 with AsF3 in aHF yield [Ln(AsF3)3](AsF6)3 which are stable in a dynamic vacuum at temperatures lower than 233 K. In reactions between M(AF6)2 (M: alkaline earth metal and Pb, A: As, Sb) and XeF2 in aHF as a solvent, compounds of the type [M(XeF2)n](AF6)2 were synthesized. Analogous reactions with AsF3 yield coordination compounds of the type [M(AsF3)n](AsF6)2. During the preparation of Mx(AsF6)x (M: metal in oxidation state x+) by the reaction between metal fluoride and excess of AsF5 in aHF it was found that HF could also act as a ligand to the metal ions (e.g. Ca(HF)(AsF6)2).  相似文献   

9.
Graphite intercalated by AsF5 has been reported to give compounds of formula C8nAsF5 where n is the stage. It is doubtful however if materials of exact composition C8nAsF5 have ever been obtained. The intercalation of graphite by AsF5 is associated with electron oxidation of the graphite according to the equation: 3AsF5 + 2e? → 2AsF6? + AsF3. Because of the easy removal or displacement of AsF3 the As:F ratio is readily increased beyond 5. By treating graphite with excess AsF5, removing volatiles under vacuum and repeating the cycle seven times a first stage salt C10+AsF6? (Co = 7.96 ā) is made. Interaction of graphite with AsFs in the molar ratio 8:1, within a small volume reactor, yields a material of approximate composition C8AsF5. The major component of the volatiles at the onset of their removal is AsF5,, but, at a composition close to C10AsF5, is AsF3. ‘Graphite AsF5’ can be prepared by adding AsF3 to CxAsF6 salts. The electrical conductivities of ‘AsF5’ and AsF6 relatives will be compared and discussed.  相似文献   

10.
Mononuclear palladium-hydroxo complexes of the type [Pd(N-N)(C6F5)(OH)] [(N-N)=2,2-bipyridine (bipy), 4,4-dimethyl-2,2-bipyridine (Me2bipy), or N,N,N,N-tetramethylethylenediamine (tmeda)] react with silanols HOSiR3 in toluene giving the corresponding siloxo complexes [Pd(N-N)(C6F5)(OSiR3)]. The X-ray crystal structure of [Pd(tmeda)(C6F5)(OSiPh3)] has been determined. In one of the two molecules in the asymmetric unit there is an intramolecular interaction by phenyl-pentafluorophenyl π-stacking.  相似文献   

11.
Tin(II) fluoride reacts with Lewis acids, AsF5 and SbF5, in a 2:1 ratio, to give salts of the [Sn2F3+] cation. Reaction of SnF·MF6 with SnF2 in liquid SO2 also produces the [Sn2F3] [MF6] salt. Tin-119 Mössbauer data are presented and compared with those for SnF2, SnF·MF6 and Sn(SbF6)2.  相似文献   

12.
K3InF6 is synthesized by a sol-gel route starting from indium and potassium acetates dissolved in isopropanol in the stoichiometry 1:3, with trifluoroacetic acid as fluorinating agent. The crystal structures of the organic precursors were solved by X-ray diffraction methods on single crystals. Three organic compounds were isolated and identified: K2InC10O10H6F9, K3InC12O14H4F18 and K3InC12O12F18. The first one, deficient in potassium in comparison with the initial stoichiometry, is unstable. In its crystal structure, acetate as well as trifluoroacetate anions are coordinated to the indium atom. The two other precursors are obtained, respectively, by quick and slow evaporation of the solution. They correspond to the final organic compounds, which give K3InF6 by decomposition at high temperature. The crystal structure of K3InC12O14H4F18 is characterized by complex anions [In(CF3COO)4(OHx)2](5−2x)− and isolated [CF3COOH2−x](x−1)− molecules with x=2 or 1, surrounded by K+ cations. The crystal structure of K3InC12O12F18 is only constituted by complex anions [In(CF3COO)6]3− and K+ cations. For all these compounds, potassium cations ensure only the electroneutrality of the structure. IR spectra of K2InC10O10H6F9 and K3InC12O12F18 were also performed at room temperature on pulverized crystals.  相似文献   

13.
Arsenic pentafluoride reacts with excess copper in sulphur dioxide to give CuAsF6. A similar reaction with elemental nickel yields Ni(AsF6)2.2SO2, the structure of which is discussed. The X-ray powder diffraction photograph of CuAsF6 was indexed on a rhombohedral unit cells a = 5.49±.01Å, α = 55.7±.1°, V = 105.4Å3, Z = 1, and is of the same structural type as LiSbF6 showing that the cuprous ion is octahedrally surrounded by fluorines. Comparison of the unit cell volume of CuAsF6 with other structurally similar hexafluoroarsenate salts shows that the effective volume of cuprous ion is small indicating substantial anion-cation interaction. Arsenic pentafluoride reacts with Monel in the presence of sulphur dioxide give a mixtures of CuAsF6 and Ni[AsF6]2.2SO2.  相似文献   

14.
The synthesis and the crystal structure of Cs2Nb6Br5F12 containing octahedral niobium clusters are presented in this work. This bromofluoride is based on a Nb6Li12Fa6 (L=Br and F) unit and crystallizes in the orthorhombic system (space group, Cccm; Z=4; a=9.2446(2) Å, b=13.6256(3) Å, and c=17.1665(4) Å; R=0.0241). Fluorine and bromine are randomly distributed on the inner ligand positions, Li, that edge-bridge the Nb6 cluster whereas fluorine fully occupies the apical positions (La). The units are linked to each other by apical ligands leading to an original one-dimensional unit connection. The cesium atoms are statistically distributed on several sites that describe parallel channels along the [1 0 0] direction. The influence of fluorine ligands upon the stabilization of this structure type as well as the structural relationships with Ba2Zr6Cl17(B), Nb6F15, and NaMo6Cl13 will be evidenced and discussed.  相似文献   

15.
The Ni-methyl complex (η5-C5H5)Ni(CH3)(PPh3) (1) reacted with B(C6F5)3 to give an unstable contact ion-pair complex with a μ-methyl bridge between the Ni and B atoms. Formation of the B-CH3 bond was confirmed by the reaction of this complex with PPh3 to give [(η5-C5H5)Ni(PPh3)2][B(CH3)(C6F5)3] which was structurally characterized. Spontaneous decomposition of the contact ion-pair complex yielded (η5-C5H5)Ni(C6F5)(PPh3) which is very stable and does not show any reactions with norbornene with or without added B(C6F5)3. 19F NMR study showed that the polynorbornene obtained by the catalysis of 1/B(C6F5)3 system has the C6F5 end-group. A series of reactions, which includes CH3/C6F5 exchange between the Ni and B centers with concomitant dissociation of PPh3 to accept coordination of a norbornene monomer, is proposed as the route to active species that can initiate vinyl polymerization of norbornene.  相似文献   

16.
The anhydrous salt K2B12F12 crystallized from aqueous solution and its structure was determined by single crystal X-ray diffraction. The Ni2In-type structure it exhibits is rare for an A2X ionic compound at 25 °C and 1 atm., consisting of an expanded hexagonal close-packed array of B12F122− centroids (cent?cent distances: 7.204-8.236 Å) with half of the K+ ions filling all of the Oh holes and half of the K+ ions filling all of the D3h trigonal holes in the close-packed layers that are midway between two “empty” Td holes. The structure is also unusual in that the bond-valence sum for the K+ ions in Oh holes is less than or equal to 0.73 (the bond-valence sum for the other type of K+ ion is 1.16). A variation of the Ni2In structure is exhibited by the previously published monohydrate Cs2(H2O)B12F12, for which an improved structure is also reported here. For K2B12F12: monoclinic, C2/c, a = 8.2072(8), b = 14.2818(7), c = 11.3441(9) Å, β = 92.832(5)°, Z = 4, T = 120(2) K. For Cs2(H2O)B12F12: orthorhombic, P212121, a = 9.7475(4), b = 10.2579(4), c = 15.0549(5) Å, Z = 4, T = 110(1) K.  相似文献   

17.
Asymmetric ditertiary stibine sulfides (C6H5)(CH3)(S)SbCH2Sb(CH3)(C6H5) and [(C6H5)(CH3)(S)Sb]2(CH2)3 have been prepared. It was found that they exist as only one of two possible diastereomers in the crystalline state. However, isomerization to the other form takes place in solution, resulting in an equilibrium mixture. A possibility of configurational lability of tertiary stibine sulfide was suggested for the first time.  相似文献   

18.
The effects of irradiation doses, irradiation temperature and a combined treatment of irradiation and cooking on the vitamin B6 and B12 contents of grass prawns have been studied. Grass prawns were irradiated at refrigerated (4°C) or frozen (-20°C) temperatures with different doses. A domestic cooking procedure was followed after irradiation. The changes in vitamins B6 and B12 of both raw and cooked grass prawns were evaluated. Results showed no significant changes of vitamin B6 and B12 in grass prawns with a radiation dose up to 7 kGy at either 4°C or -20°C. Irradiation at 4°C caused more destruction of vitamin B12 but not vitamin B6 than did irradiation at -20°C in grass prawns. There was significant destruction of both vitamins B6 and B12 in unirradiated samples during cooking. The introduction of the irradiation process before cooking had no effect on either vitamin. These results indicate that the loss of vitamins B6 and B12 in the combined treatments was caused mainly by thermal destruction.  相似文献   

19.
A new method for the preparation of bis(perfluoroorgano) zinc compounds is described: CF3I and C6F5I react with dialkylzinc in the presence of a Lewis base quantitatively to give (CF3)2Zn and (C6F5)2Zn complexes, while the analogous reactions with C2F5I and iC3F7I do not yield the pure compounds. 1H, 19F n.m.r, i.r. and Raman spectra are presented.  相似文献   

20.
Ampoule reactions of C70 with n- and i-C3F7I were carried out at 250-310 °C. Two step HPLC separations allowed the isolation of several C70(n-C3F7)4-8 and C70(i-C3F7)4 compounds. Crystal and molecular structures of C70(n-C3F7)8-V, C70(n-C3F7)6O, C70(n-C3F7)4, and three isomers of C70(i-C3F7)4 have been determined by X-ray crystallography using synchrotron radiation. Molecular structures of the new compounds were compared with the known examples and discussed in terms of addition patterns and relative energies of their formation.  相似文献   

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