Beiträge zur Chemie des Phosphors. 157. Dilithium-hexadecaphosphid,Li2P16: Darstellung aus Li2HP7 und 31P-NMR-spektroskopische Strukturbestimmung

Contributions to the Chemistry of Phosphorus. 157. Dilithium Hexadecaphosphide, Li₂P₁₆: Preparation from Li₂HP₇ and Structure Determination by ³¹P-NMR Spectroscopy . Dilithium hexadecaphosphide, Li₂P₁₆ ( 1 ), is purely obtained as a crystalline solvent adduct Li₂P₁₆ · 8 THF by the disproportionation of Li₂HP₇ in tetrahydrofuran under suitable conditions. The constitution of 1 has been deduced from its 1D- and 2D-³¹P-NMR spectrum (in dimethylformamide). The structure of the P₁₆^2? ion in solution is identical with that in solid (Ph₄P)₂P₁₆ [20]. As a conjuncto-phosphane the P₁₆^2? is made up of two P₉(3)^?-unit groups analogous to deltacyclane, which are linked via the diatomic bridges as a common zero-bridge.     

Beiträge zur Chemie des Phosphors. 151. Dilithium-dihydrogentetradecaphosphid,Li2H2P14: Darstellung und strukturelle Charakterisierung

Contributions to the Chemistry of Phosphorus. 151. Dilithium Dihydrogen Tetradecaphosphide, Li₂H₂P₁₄: Preparation and Structural Characterization Dilithium dihydrogentetradecaphosphide, Li₂H₂P₁₄ ( 1 ), is obtained as an orange-red solvent adduct Li₂H₂P₁₄ · 6 THF in a purity of 80–90 per cent by reacting P₂H₄ with n-BuLi under suitable conditions. 1 is also formed in the reaction of Li₃P₇ or LiH₄P₅ with P₂H₄, and in the disproportionation of LiH₄P₇. According to its 2D-³¹P-NMR spectrum 1 is a conjuncto-phosphane built up by one P₇(5)^?- and one P₉(3)^?-unit group with structures analogous to norbornane and delta-cyclane, respectively.     

Niob- und Tantalkomplexe mit P2- und P4-Liganden

Niobium and Tantalum Complexes with P₂ and P₄ Ligands The photolysis of [Cp″Ta(CO)₄] 1 (Cp″ = C₅H₃^tBu₂?1,3) and P₄ affords Cp″(CO)₂Ta(η⁴?P₄) 2 , [{Cp″(CO)Ta}₂(m??η^2:2?P₂)₂] 3 and [Cp₃″(CO)₃Ta₃(P₂)₂] 4 . In a photochemical reaction 2 and [Cp*Nb(CO)₄] 5 form [{Cp*(CO)Nb}{Cp″(CO)Ta}(m??η^2:2?P₂)₂] 6 and [{Cp*(CO)₂Nb} {Cp*Nb}{Cp″(CO)Ta}(m?₃?η^2:1:1?P₂)₂] 7 , a compound with the novel m?₃?η^2:2:1?P₂-coordination mode. The reaction of 2 and [Cp*Co(C₂H₄)₂] 8 leads to [{Cp*Co} {Cp″(CO)Ta}(m??η^2:2?P₂)₂] 9 , a heteronuclear complex with an ?early”? and a ?late”? transition metal. Complexes 2, 3, 7 and 9 have been further characterized by X-ray structure analyses.     

Synthese und Kristallstruktur von Na10[P4(NH)6N4](NH2)6(NH3)0,5 mit dem adamantanartig aufgebauten Anion [P4(NH)6N4]4−

Synthesis and Crystal Structure of Na₁₀[P₄(NH)₆N₄](NH₂)₆(NH₃)_0.5 with an Adamantane-like Anion [P₄(NH)₆N₄]^4? Crystals of Na₁₀[P₄(NH)₆N₄](NH₂)₆(NH₃)_0.5 were obtained by the reaction of P₃N₅ with NaNH₂ (molar ratio 1:20) within 5 d at 600°C in autoclaves. The following data characterize X-ray investigations: Fm3 m, Z = 8, a = 15.423(2) Å, Z(F) = 261 with F ≥ 3 σ(F) Z(Variables) = 27, R/R_w = 0.086/0.089 The compound contains the hitherto unknown anion [P₄(NH)₆N₄]^4?, which resembles adamantane. The total structure can be described as follows: The centers of gravity of units of [Na₈(NH₂)₆(NH₃)]²⁺ – 8Na⁺ on the corners of a cube, 6NH₂^? on the ones of an inscribed octahedron with NH₃ in the center – follow the motif of a cubic-closest packed arrangement. Units of [Na₁₂(NH₂)₆]⁶⁺ – 12Na⁺ on the corners of a cuboctahedron and 6NH₂^? on the ones of an inscribed octahedron – occupy all octahedral and those of [P₄(NH)₆N₄]^4? all tetrahedral sites.     

Beiträge zur Chemie des Phosphors. 162. MP19 (MI  Li,Na, K), die ersten Salze mit Nonadecaphosphid(3-)-Ionen

Contributions to the Chemistry of Phosphorus. 162. M P₁₉ (M^I ? Li, Na, K), the First Salts with Nonadecaphosphide (3-) Ions The nonadecaphosphides Li₃P₁₉, Na₃P₁₉, and K₃P₁₉ are formed besides other polyphosphides by the nucleophilic cleavage of white phosphorus with lithium dihydrogenphosphide or sodium and potassium, respectively. Li₃P₁₉ also results from the reaction of Li₃P₇ with white phosphorus or iodine or 1, 2-dibromoethane, as well as from the degradation of Li₂P₁₆ with lithium dihydrogenphosphide. According to 2D-³¹P-NMR-spectroscopic investigations the P₁₉^3? ion is a conjuncto-phosphane made up of a central P₅^? structural element and two Pg(3)^? unit groups analogous to deltacyclane. The nonadecaphosphides M₃^IP₁₉ are intermediates in the formation of hexadecaphosphides MP₁₆ from heptaphosphides MP₇.     

Calix[4]pyrrole‐Based Heteroditopic Ion‐Pair Receptor That Displays Anion‐Modulated,Cation‐Binding Behavior

A new ditopic ion‐pair receptor 1 was designed, synthesized, and characterized. Detailed binding studies served to confirm that this receptor binds fluoride and chloride ions (studied as their tetraalkylammonium salts) and forms stable 1:1 complexes in CDCl₃. Treatment of the halide‐ion complexes of 1 with Group I and II metal ions (Li⁺, Na⁺, K⁺, Cs⁺, Mg²⁺, and Ca²⁺; studied as their perchlorate salts in CD₃CN) revealed unique interactions that were found to depend on both the choice of the added cation and the precomplexed anion. In the case of the fluoride complex [ 1? F]^? (preformed as the tetrabutylammonium (TBA⁺) complex), little evidence of interaction with the K⁺ ion was seen. In contrast, when this same complex (i.e., [ 1? F]^? as the TBA⁺ salt) was treated with the Li⁺ or Na⁺ ions, complete decomplexation of the receptor‐bound fluoride ion was observed. In sharp contrast to what was seen with Li⁺, Na⁺, and K⁺, treating complex [ 1? F]^? with the Cs⁺ ion gave rise to a stable, receptor‐bound ion‐pair complex [Cs ?1? F] that contains the Cs⁺ ion complexed within the cup‐like cavity of the calix[4]pyrrole, which in turn was stabilized in its cone conformation. Different complexation behavior was observed in the case of the chloride complex [ 1? Cl]^?. In this case, no appreciable interaction was observed with Na⁺ or K⁺. In addition, treating [ 1? Cl]^? with Li⁺ produces a tightly hydrated dimeric ion‐pair complex [ 1? LiCl(H₂O)]₂ in which two Li⁺ ions are bound to the crown moiety of the two receptors. In analogy to what was seen in the case of [ 1? F]^?, exposure of [ 1? Cl]^? to the Cs⁺ ion gives rise to an ion‐pair complex [Cs ?1? Cl] in which the cation is bound within the cup of the calix[4]pyrrole. Different complexation modes were also observed when the binding of the fluoride ion was studied by using the tetramethylammonium and tetraethylammonium salts.     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 42. Trilithiumheptaphosphid Li3P7: Darstellung,Struktur und Eigenschaften

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 42. Trilithiumheptaphosphide Li₃P₇: Preparation, Structure, and Properties Trilithium heptaphosphide, Li₃P₇, has been prepared by reaction of the elements at 870 K in Nb and Ta ampoules, respectively. The bright yellow (solventfree) substance crystallizes in a new structure type (P2₁2₁2₁; a = 974.2(1) pm; b = 1053,5(1) pm; c = 759,6(1) pm; Z = 4). The structure is closely related to the plastically crystalline Rb₃P₇ type of structure (Li₃Bi variant). The heptaphosphanortricyclene anions P₇^3? are surrounded by 12 Li cations and connected one to each other in a complex manner. The anion exhibits a differentation of distances and angles typical for ionic nortricyclenes X₇^3? (P? P distances: d?(basis) = 224.9 pm; d?(basis-bridge) = 214.7 pm; d?(bridge-bridgehead) = 217.6 pm). The distances Li to P are in the range of 250 ≤ d(Li? (2b)P^?) ≤ 270 pm. The P? P and Li? P bond distances are equivalent to meaningful Pauling bond orders PBO. On heating in closed ampoules, Li₃P₇ shows an endothermic effect at 900 K, corresponding to a first order phase transition into a HT phase of unknown nature up to now. On thermal decomposition no congruent dissociative sublimation occurs in contrast to the other heptaphosphides M₃P₇, but LiP and Li₃P are formed, the latter evaporates congruently dissociative, Solutions of Li₃P₇ in en show valence fluctuation of the P₇^3? anions already at room temperature (δ ³¹P-NMR = ? 122.1). Further reactions of Li₃P₇ are reported as well as the structural differences between Li₃P₇ and the solvates Li₃P_7solv3 are discussed.     

Komplexchemie P-reicher Phosphane und Silylphosphane. X [1] Zum Einfluß der Komplexierung auf die Reaktivität des [(Me3Si)2P]2PH

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. X. The Influence of the Formation of Complex Compounds on the Reactivity of [(Me₃Si)₂P]₂PH Whereas [(Me₃Si)₂P]₂PH 1 by BuLi is attacked at the PH group to give [(Me₃Si)₂P]₂PLi 2 , the related chromium carbonyl complex (Me₃Si)P^IV ? ²P^IV(H) ? ³P^III(Si? Me₃)₂ · Cr(CO)₄ 3 with BuLi yields Li(Me₃Si)¹P^IV ? ²P^IV(H) ? ³P^III(SiMe₃)₂ · Cr(CO)₄ 4 by cleaving a Si? P bond at the chromium substituted ¹P atom. Dissolved in ether, 4 is stable for a longer time, while under comparable conditions 2 forms Li₃P₇ which is not obtained from 4 . MeOH in 3 cleaves selectively the Me₃Si groups from the complex substituted P atom yielding (Me₃Si)(H)¹P^IV ? ²P^IV(H) ? ³P^III(SiMe₃)₂ · Cr(CO)₄ 5 and HP^IV ? ²P^IV(H) ? ³P^III(SiMe₃)₂Cr(CO)₄ 6. 5 and 6 seem to be stable in contrast to the uncoordinated triphosphanes which are not known.     

Beiträge zur Chemie des Phosphors. 140. Dilithium-hydrogenheptaphosphid,Li2HP7 – ein teilmetalliertes Derivat von P7H3: Darstellung und strukturelle Charakterisierung

Contributions to the Chemistry of Phosphorus. 140. Dilithium Hydrogen Heptaphosphide, Li₂HP₇ — a Partially Metallated Derivative of P₇H₃: Preparation and Structural. Characterization Dilithium hydrogen heptaphosphide, Li₂HP₇ ( 2 ), is purely obtained as an orange-red solvent adduct by reacting P₂H₄ with n-BuLi or Li₃P₇ ( 1 ) under suitable conditions. 2 is also formed in the metalation of LiH₂P₇ ( 3 ) or P₇H₃, in the disproportionation of LiH₄P₅, in thepartial protolysis of 1 , and in the nucleophilic cleavage of P₄. The composition and the structure of 2 could be elucidated by a complete analysis of its low-temperature ³¹P{¹H}-NMR spectrum. As shown by the δ(³¹P) values, the P₇ cage in 2 is clearly distorted compared with 1 . The P₇H^2? ion has fluctuating bonds in analogy to dihydrobullvalene and can be described by two valence-tautomeric forms with identical structures. At room temperature 2 disproportionates yielding lithium polyphosphides with a greater number of phosphorus atoms.     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 44. Tricäsiumheptaphosphid Cs3P7: Darstellung,Struktur und Eigenschaften

Chemistry and Structural Chemistry of Phosphides and Ployphosphides. 44. Tricesium Heptaphosphide Cs₃P₇: Preparation, Structure, and Properties Tricesium heptaphosphide is prepared from the elements by a quantitative reaction at 1200 K in Nb ampoules. Slow cooling yield the bright yellow α-Cs₃P₇, quenching the yellow orange coloured β-Cs₃P₇. The crystalline α-Cs₃P₇ transforms at 552 K in a first order phase transition to the plastically crystalline β-Cs₃P₇. Both modifications are sensitive against moisture and oxygen and are completely soluble in ethylendiamine yielding a pale yellow solution. At room temperature the ³¹P nmr spectra of such solutions show only one singulett, which corresponds to the valence tautomerism of the P₇^3? anion. α-Cs₃P₇ crystallizes in a new structure type (P4₁, a = 904.6(1) pm; c = 1671.4(4) pm; Z = 4). The structure is formed by heptaphospha-nortricyclene anions P₇^3? and Cs⁺ cations. The cs atoms connect the anions forming a three-dimensional arrangement (d?(Cs? P) = 374 pm), not allowing the fragmentation into discrete Cs₃P₇ units. The P? P distances differ by their function in the nortricyclene anion. Each P₇ group is surrounded by 12 Cs atms. β-Cs₃P₇ crystallizes in the Li₃Bi type of structure (Fm3 M; a(573 K) = 1130.5(1)pm; Z = 4). The P atoms of the P₇^3? anions surround the Bi positions with an orienational disorder. The orientation has been investigated with a mixed crystal Ca₃(P₇)_2/3(P₁₁)_1/2 (Fm3 m; a (298 K) = 1149.5(9) pm; Z = 4).     

Zur Überwindung von Vorurteilen: Das erste basische Oxoindat,Na26O3[InO4]4

The First Basic Oxoindate: Na₂₆O₃[InO₄]₄ For the first time Na₂₆O₃[InO₄]₄ was obtained by annealing intimate mixtures of Na₂O, CdO and elemental In (molar ratio 3.5:1.0:2.0) in closed Ni-cylinders (30 days, 600°C) in form of yellow single crystals. The structure determination by four circle diffractometer data (MoKα, 921 out of 921 I_o(hkl), R = 2.53, R_w = 2.18%) confirms the space group 143d (cubic) with a = 1 427.37 pm and Z = 4. All kation are surrounded by tetrahedron of O^2?. In³⁺ is coordinated with O(1) and O(2) (without O(3)) only. There are ?isolated”? [InO₄]-tetrahedra. The Madelung Part of Lattice Energy, MAPLE, the Mean Fictive Ionic Radii, MEFIR, Effective Coordination Numbers, ECoN, and Charge Distribution, CHARDI, are calculated.     

The crystal structure of Na7Mg4.5(P2O7)4

The crystal structure of Na₇Mg_4.5(P₂O₇)₄ has been solved by direct methods from the three-dimensional X-ray data. The space group is $\text{P}\text{1}$. The crystal structure consists of Mg²⁺, Na⁺, and P₂O^4?₇ ions. One magnesium atom at symmetry center (0,0,0) and two sodium atoms at ±(?0.0421, ?0.0596, 0.2230) display occupation factors 0.5 each. A short interatomic distance between these Na⁺ and Mg²⁺ ions (1.80 ± 0.01 Å) excludes the occupation of both sites in the same unit cell. The crystal structure of Na₇Mg_4.5(P₂O₇)₄ consists of unit cells containing Na₈Mg₄(P₂O₇)₄ or Na₆Mg₅(P₂O₇)₄ with a statistical occurrence 1:1.Each Mg²⁺ ion is octahedrally coordinated by six O^2? ions at distances 1.979 – 2.270 Å. The coordination polyhedra around the Na⁺ ions are ill-defined. The bond angles POP in the P₂O^4?₇ groups are 126.6 and 133.6° (±0.3°). The final reliability factor R is 7.1%.     

Notiz über Li2PdO2

Note on Li₂PdO₂ For the first time we prepared ruby-red single crystals of Li₂PdO₂ by reaction with the wall 3 Na₂O + Li₂O₂ + ?Tb₄O₇”?(+ Pd) = 3 Na₂TbO₃ + Li₂PdO₂ + ?TbO₂”?, Pd-tube, 1100°C, 7 d. Single crystal data confirm the Li₂CuO₂-type of structure [a = 375.34(5), b = 298.18(4), c = 931.58(10) pm; spacegroup Immm; d_x = 4.85 g · cm^?3; 144 I₀(hkl); R = 3.54%, Rw = 3.19%; MoKα ; four-circle diffractometer Philips PW 1100] and reveal clearly different parameters compared with those deduced by powder data. The Madelung Part of Lattice Energy, MAPLE, corresponds now to the sum of the MAPLE values of the binary oxides.     

Na7Y2(P2O7)2 (P3O10) – A New Layer and Tunnel Structure

A new layered phosphate, Na₇Y₂(P₂O₇) ₂(P₃O₁₀), containing both [P₂O₇]^4? and [P₃O₁₀]^5? groups, has been prepared. It crystallizes in the monoclinic space group P2/c with a = 16.205(4), b = 5.3746(9), c = 12.309(4) Å, β = 97.96(2)°, V = 1061.7(5) ų and Z = 2. The structure was solved and refined to R₁ = 0.0298 and wR₂ = 0.0698 for 1844 independent reflections with I > 2σ(I). It consists of layers of corner and edge-sharing YO₇ polyhedra, P₂O₇ and P₃O₁₀ groups. Each layer is built up from two parallel [YP₂O₇] slabs, held together by the P₃O₁₀ groups. This arrangement gives rise to intersecting tunnels within the layer. The Na⁺ cations are located in the tunnels and between the layers. Both P₂O₇ and P₃O₁₀ groups contain unshared oxygen atoms directed toward the interlayer space and toward the tunnels. The P₂O₇ groups show a staggered configuration. In addition to this original layered framework, the title compound provides the third example of a compound containing a mixed anion of [P₂O₇]^4? and [P₃O₁₀]^5?. The structure was compared with the two previously reported ones, containing such a mixed anion: NH₄Cd₆(P₂O₇) ₂(P₃O₁₀) [6] and Cs₂Mo₅O₂(P₂O₇)₃ · (P₃O₁₀) [7].     

Beiträge zur Chemie des Phosphors. 245 [1], LiP7(BNEt2)2 und P7(BNEt2)4Cl: Zwei neuartige polycyclische Boraphosphane

Contributions to the Chemistry of Phosphorus. 245, LiP₇(BNEt₂)₂ and P₇(BNEt₂)₄Cl: Two Novel Polycyclic Boraphosphanes The directed synthesis of a noval tetracyclic heteropolyphosphane skeleton from a tricyclophosphane has been achieved by condensation of Li₃P₇ · 3DME with Cl(Et₂N)B‐B(NEt₂)Cl to the diboranonaphosphanide LiP₇(BNEt₂)₂ ( 1 ). When the reaction proceeds the mixed‐substituted diboranonaphosphane P₇(BNEt₂)₄Cl ( 2 ) is formed. According to their ³¹P NMR spectra 1 and 2 possess a B₂P₇(3) skeleton analogous to that of the hydrocarbon deltacyclane. Additional weak signals in the ³¹P NMR spectrum of 2 indicate that also small amounts of the symmetrically substituted diborane(4) P₁₄B₆(NEt₂)₆ ( 3 ) are formed.     

Kettenverlängerung am P2(SiMe3)4 durch Reaktion mit LiBu

Extension of the Chain Length of P₂(SiMe₃)₄ by Reaction with LiBu The first steps of the reaction of P₂(SiMe₃)₄ 1 with LiBu in THF, which finally yields Li₃P₇ among other P-rich phosphides while P(SiMe₃)₃ and LiP(SiMe₃)₂ are simultaneously split off, were investigated by means of ³¹P-NMR spectroscopy. At ?20°C first of all one Si? P bond is cleaved generating Li(Me₃Si)P? P(SiMe₃)₂ 2 as well as BuSiMe₃. Subsequently 2 forms Li(Me₃Si)P? P(SiMe₃)? P(SiMe₃)₂ 5 and LiP(SiMe₃)₂ 4 in equimolar ratios. This clearly demonstrates that both compounds are generated in one single reaction step. This behaviour is caused by the different basicity of the respective P-atoms in 2 , which necessarily results in a multicentered mechanism.     

Li+ ion conductivity in the system Li4SiO4Li3VO4

Two ranges of solid solutions were prepared in the system Li₄SiO₄Li₃VO₄: Li_4?xSi_1?xV_xO₄, 0 < x ? 0.37 with the Li₄SiO₄ structure and Li_3+yV_1?ySi_yO₄, 0.18 ? y ? 0.53 with a γ structure. The conductivity of both solid solutions is much higher than that of the end members and passes through a maximum at ～40Li₄SiO₄ · 60Li₃VO₄ with values of ～1 × 10^?5 ohm^?1 cm^?1 at 20°C, rising to ～4 × 10^?2 ohm^?1 cm^?1 at 300°C. These conductivities are several times higher than in the corresponding Li₄SiO₄Li₃(P,As)O₄ systems, especially at room temperature. The solid solutions are easy to prepare, are stable in air, and maintain their conductivity with time. The mechanism of conduction is discussed in terms of the random-walk equation for conductivity and the significance of the term c(1 ? c) in the preexponential factor is assessed. Data for the three systems Li₄SiO₄Li₃YO₄ (Y = P, As. V) are compared.     

Ein neues Cobaltat mit Inselstruktur: Li6[CoO4]

A New Cobaltate with Isolated Anion Structure: Li₆[CoO₄] For the first time transparent, blue single crystals of Li₆[CoO₄] have been prepared (Li₂O/Na₂O/?CoO”? (Li:Na:Co = 1.3:1.3:1), Co-tube, 580°C, 22 d). Corresponding to Li₆□CoO; it is an ordered variant of the Li₂O-type of structure: P4₂/nmc; a = 653.6(1) pm, c = 465.4(1) pm; Z = 2; d_x = 2.75 g cm^?3, d_pyk = 2.71 g cm^?3 (4-circle-diffractometer-data (PW 1100), AgKα; 230 from 936 I₀(hkl); R = 9.58%, R_W = 5.25%). Parameters see text. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated and discussed. The magnetic properties are measured in the temperature range of 14–297 K.     

Beiträge zur Chemie des Phosphors. 172. Existenz und Charakterisierung des Pentaphosphacyclopentadienid-Anions,P5−, des Tetraphosphacyclopentadienid-Ions,P4CH−, und des Triphosphacyclobutenid-Ions,P3CH2−

Contributions to the Chemistry of Phosphorus. 172. Existence and Characterization of the Pentaphosphacyclopentadienide Anion, P₅^?, the Tetraphosphacyclopentadienide Ion, P₄CH^?, and the Triphosphacyclobutenide Ion, P₃CH₂^? The pentaphosphacyclopentadienide anion, P₅^? ( 1 ), the tetraphosphacyclopentadienide ion, P₄CH^?( 2 ), and the triphosphacyclobutenide ion, P₃CH₂^?( 3 ), are formed besides other polyphosphides by the nucleophilic cleavage of white phosphorus with sodium in diglyme. 1 also results from the reaction of lithium dihydrogenphosphide with white phosphorus and can be obtained pure in the form of a LiP₅ solution after separating the other products. The common structural feature of 1, 2 , and 3 are rings with unsubstituted P atoms of coordination number 2 that are stabilized by mesomerism.     

Comparative investigations of LiVPO4F/C and Li3V2(PO4)3/C synthesized in similar soft chemical route

Triclinic LiVPO₄F and monoclinic Li₃V₂(PO₄)₃ are synthesized through a soft chemical process with mechanical activation assist, followed by annealing. In this process, ascorbic acid is used as reducing agent as well as carbon source. The as-prepared samples are coated with amorphous carbon. XPS analysis results show the expected valency states of ions in LiVPO₄F and Li₃V₂(PO₄)₃. The electrochemical properties of the prepared LiVPO₄F/C and Li₃V₂(PO₄)₃/C cathodes are evaluated. The as-prepared LiVPO₄F/C cathode shows an initial discharge specific capacity of 140?±?3 mAh?g^?1 at 30 mA?g^?1 in the voltage range of 3.0~4.4 V, compared with that of 138?±?3 mAh?g^?1 possessed by Li₃V₂(PO₄)₃/C. Both samples exhibit good cycle performance at different current densities. The capacity delivered by LiVPO₄F remains 95.5 and 91.7 % of its initial discharge capacity after 50 cycles at 150 and 750 mA?g^?1, respectively, while 97.4 and 90.6 % for Li₃V₂(PO₄)₃/C. But the rate capability of LiVPO₄F/C is not so good compared with as-prepared Li₃V₂(PO₄)₃/C.