The volumetric analysis of phosphates

A method has been developed for the volumetric determination of orthophosphate, and a simple variation permits the determination of the average number of phosphorus atoms per molecule in condensed phosphates. For total P₂O₅ the phosphates are converted to the diacid orthosalt and precipitated as silver phosphate. The liberated acid is then titrated. For determination of chain length the condensed phosphate is converted to the diacid form and treated similarly, then hydrolysed and determined as orthophosphate. The ratio of the two titrations is equal to the average number of phosphorus atoms per molecule.     

9Be and 31P NMR analyses on the influence of imino groups on Be2+ complex stabilities of a series of cyclo‐μ‐imido triphosphate anions

The complexation behaviors of Be²⁺ with cyclo‐μ‐imido triphosphate anions, cP₃O_9?n(NH)_n^3? (n = 1, 2), have been investigated by both ⁹Be and ³¹P NMR techniques at ?2.3 °C in order to clarify the coordination structures of the complexes. The spectra showed that cP₃O_9?n(NH)_n (n = 1, 2) ligands form ML, ML₂, and M₂L complexes with Be²⁺ ions, and the formation of complexes coordinating with nitrogen atoms of the cyclic framework in the ligand molecule has been excluded. These complexation trends are very similar to those of Be²⁺‐cP₃O₆(NH)₃^3? system, which has been reported by us. The peak deconvolution of ⁹Be NMR spectra made these beryllium complexes amenable to stability constant determinations. The stability constants of the complexes increase with an increase in the protonation constants of the ligands as the number of imino groups, which constitute the ligand molecules, is ascended. This increase is primarily attributable to the lower electronegativity of nitrogen atoms than oxygen atoms, which are directly bonded to central phosphorus atoms; moreover, tautomerism equilibrium in the entire of the imidopolyphosphate molecule is also responsible to the higher basicity. ³¹P NMR spectra measured concurrently have verified the formation of the complexes estimated by the ⁹Be NMR measurement. Intrinsic ³¹P NMR chemical shift values of the phosphorus atoms belonging to ligand molecules complexed with Be²⁺ cations have been determined. Not only the protonation constants but also the stability constants of all Be²⁺ complexes increase approximately linearly with an increase in the number of imino groups. Copyright © 2013 John Wiley & Sons, Ltd.     

Hochauflösende 31P-Festkörper-NMR bei 109,3 MHz an den Pentanatrium-catena-triphosphaten Na5P3O10-I,Na5P3O10-II und Na5P3O10 · 6 H2O

High-resolution Solid-state ³¹P NMR at 109.3 MHz of Penta-sodium Catena-triphosphates, Na₅P₃O₁₀-I, Na₅P₃O₁₀-II, and Na₅P₃O₁₀ · 6 H₂O Using high-resolution solid-state ³¹P n.m.r. exact values of the isotropic chemical shift, the chemical shift anisotropy, and the asymmetry parameter of the PO₄ units (end and middle groups) of the three penta-sodium catena-triphosphates Na₅P₃O₁₀-I, Na₅P₃O₁₀-II, and Na₅P₃O₁₀ · 6 H₂O have been determined. Although the geometries of the P₃O₁₀^5? anions of the three polycrystalline phases are not very different, the afore-mentioned NMR parameters show significant differences for each PO₄ tetrahedron. Starting from a semi-quantitative theory of the ³¹P chemical shift of phosphates the differences between the isotropic chemical shifts of the end and middle groups are rationalized in terms of differences of the electronegativities of the terminal and bridging oxygens. This interpretation differs from that given by Andrew et al. [3].     

不同结构的磷酸盐对凝胶体系中草酸钙晶体物相和相组成的影响

泌尿系结石的形成是一种病理性生物矿化过程，不同地区的结石发病率在3％～15％之间。且50％(美国)至80％(中国)的人会复发。结石中约70％以上为草酸钙(CaC2O4)结石。CaC2O4结石的形成与其热力学(过饱和度)和动力学(成核、生长和聚集)因素有关。由于结石患者尿液和正常人尿液中     

Theoretical study on the interaction of neutral and charged Tin (n = 1–7) clusters with one oxygen molecule

The interactions between the neutral and charged (?2, ?1, +1, and +2) Ti_n (n = 1–7) clusters and one O₂ molecule were investigated by density functional theory. The calculated results show that the oxygen molecule is dissociative on the neutral Ti_n clusters. Geometrically, the two O atoms are distributed at the two sides across the neutral Ti_n cluster for n = 1–4 and the oxygen atom favors the three‐fold hollow site for n = 5, 6, and 7. The binding energy per atom (E_b) and energy gap (E_gap) show higher stability and lower chemical activity of the neutral Ti_nO₂ (n = 1–7) systems compared with the corresponding Ti_n clusters. The adsorption energies (E_ad) exhibit a continuously ascending tendency except for n = 4. The results of the addition of different charges (?2, ?1, +1, and +2) on the most stable neutral Ti_nO₂ (n = 1–7) systems indicate that their geometries are usually perturbed. The stabilities of the neutral Ti_nO₂ systems are enhanced by adding one negative charge. The strongest interaction of the charged Ti_n clusters (?2, ?1, +1, and +2) with O₂ molecule is found at charge +2. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Phosphorus(III) oxide: The reaction of tetraphosphorus hexaoxide with group VIB metal carbonyls

The monosubstituted Group VIB metal carbonyl derivatives of phosphorus(III) oxide, P₄O₆, have been prepared and characterized by mass spectrometry, and IR and ³¹P NMR spectroscopy. The ³¹P NMR chemical shift of the uncoordinated phosphorus(III) atoms in the P₄O₆ cage is found to be a measure of the extent of interaction between the coordinated phosphorus atom and the Lewis acid metal carbonyl site. The P₄O₆ cage appears to be a strong π acceptor ligand.     

Festkörper‐NMR‐Untersuchungen an Natriumoxothiophosphaten(V)

Solid State NMR Investigations on Sodium Oxothiophosphates(V) Sodium monothiophosphate(V) Na₃PO₃S is dimorphic. The metastable high temperature modification β‐Na₃PO₃S crystallizes hexagonal with a = 8.996(4) and c = 5.216(2)Å. According to ³¹P solid state NMR experiments, α‐Na₃PO₃S exhibits at 20 °C a non‐axial‐symmetric environment for the phosphorus nuclei in contrast to the results of the refined crystal structure. This discrepancy is discussed assuming ordered and disordered structural models. However, at 490 °C the chemical shift tensor of the phosphorus nuclei in α‐Na₃PO₃S is axial‐symmetric. So, the distortion of the phosphorus environment is abolished by the thermal motion of the atoms. The number of crystallographically distinguishable positions for phosphorus and for sodium in Na₃PO₂S₂ and Na₃POS₃ can be confirmed in good agreement with their crystal structures using solid state NMR spectroscopy.     

Ein neues Oxophosphat (IV/III)-Anion – Darstellung und Kristallstruktur von Na6P4O10 · 2 H2O

A New Oxophosphate (IV/III) Anion – Preparation and Crystal Structure of Na₆P₄O₁₀ · 2 H₂O A new oxophosphate anion, P₄O₁₀^6?, was obtained by cleavage and simultaneous oxidation of the cyclo-hexaphosphate(III) anion in a solution of aqueous ammonia and ethanol. With sodium it forms a salt with the composition Na₆P₄O₁₀ · 2 H₂O. The crystal structure has been determined by single crystal X-ray diffraction (3 745 diffractometer data), the cell constants were obtained from X-ray powder data, space group P1 ; a = 6.004(1), b = 6.173(2), c = 11.496(2) Å, α = 99.26(2)°, β = 95.92(2)°, γ = 117.63(2)°, Z = 1, R = 0.044. The backbone of the anion is formed by phosphorus atoms directly bonded to each other. The coordination of each phosphorus atom is completed to four by oxygene. The resulting oxidation numbers are +III for the inner phosphorus atoms and +IV for the terminal phosphorus atoms. The site symmetry of the anion is approximately C_2h. Based on a ³¹P-NMR spectra of a solution the coupling constants of the AA ‘BB’ system were determined.     

31P MAS-NMR an Phosphoroxidsulfiden — experimentelle Bestimmung und quantenchemische Berechnung der Tensoren der chemischen Verschiebung

³¹P MAS-NMR of Phosphorus Oxide Sulfides — Experimental Determination and Quantumchemical Calculation of Chemical Shift Tensors By high resolution solid state ³¹P MAS NMR and analysis of spinning sidebands the principal values of the chemical shift tensors in the series P₄O₆S_n with n = 0–4 have been determined. The orientations of the corresponding principal axes within the molecules have been derived. All magnetic shielding tensors show axial symmetry within the limits of experimental error. Thus the orientation of the shielding tensor within the molecules can be deduced indirectly. This information is usually not accessible for polycrystalline samples. The principal values of the tensor of the trivalent phosphorus atoms in P₄O₆S seem to deviate considerably from those of the other compounds with respect to anisotropy and axiality. The reason is a dynamic effect: the rotation of the molecule about the PS bond. All experimental results are confirmed by ab-initio calculations using the IGLO method.     

A topological analysis of electron density and chemical bonding in cyclophosphazenes PnNnX2n (X = H, F, Cl; n = 2, 3, 4)

The restricted Hartree-Fock method was used to determine the cycle size effects on the geometric parameters of several inorganic templates, cyclophosphazenes P_nN_nX_2n (X = H, F, Cl; n = 2, 3, 4). A topological analysis of local electronic properties at the electron density critical points of bonds allowed us to quantitatively characterize the chemical bond in cyclophosphazenes and its dependence on the cycle size and substituents at phosphorus. The calculated distributions of the electron density Laplacian and electron pair localization functions revealed the special features of the electronic structure of the nitrogen and phosphorus atoms. These results explain the nature of noncovalent interactions between the P atoms of one cyclophosphazene molecule and the N atoms of the other.     

Analysis of Ligand Field Effects in Europium(III) Phosphates

Optical spectra (powder reflectance, UV/Vis/NIR region), and temperature dependent magnetic behavior (χ, μ/μ_B) were recorded for the series of anhydrous europium(III) phosphates Eu^III₃O₃(PO₄), Eu^IIIPO₄, Eu^III₂P₄O₁₃, lt- and ht-Eu^III(PO₃)₃, and Eu^IIIP₅O₁₄. By modeling within the AOM framework, the experimental data can be related to the ligand-field splitting experienced by the Eu³⁺ ions in the various mainly low-symmetry coordination environments. Our study confirms the well-established relation e_σ(Eu³⁺–O^2–) ~ d(Eu³⁺–O^2–)^–7.0 between the AOM parameter and the interatomic distance. In addition it is shown that e_σ(Eu³⁺–O^2–) depends strongly on the highly variable polarizability of the oxygen ligator atoms. This polarizability can be related to the optical basicity Λ of the various phosphates.     

The structures of europium(III)- and uranium(IV) derivatives of [P5w3oo110]15-: Evidence for “cryptohydration”

The crystal structures of (Nh₄)_11.5K_0.5[ Eu(OH₂)P₅W₃₀O₁₁₀] ·24 H₂O, K₅H₅ [Eu(OH₂)P₅W₃₀O₁₁₀] ·31 H₂O, and (NH₄)₁₁[U(OH₂)P₅Wn₃₀O₁₁₀ ·12 H₂O have been determined. In each case, the anion has the overall virtual C_5v symmetry previously observed for the sodium derivative, [NaP₅W_{30 110}]14- The encrypted Eu³⁺ and U⁴⁺cations lie on the C₅ axis, but are displaced further than the Na⁺ from the equatorial plane defined by the five phosphorus atoms. Only minor differences are observed between the structures of the two salts of the europium derivative, although solutions of these display³¹P NMR spectra with chemical shifts differing by 10 ppm, provisionally attributed to the effects of protonation of the anion, The most significant feature of the three new structures is the presence of a water molecule within the central cavity and coor-dinated to the Eu³⁺ or U⁴⁺ cation.The coordination spheres of the central cations can therefore be described as monocapped pentagonal antiprisms.     

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%.     

有机膦、胂、(月弟)合钨、钼聚多酸盐的研究 Ⅳ.烷基膦合钼聚多酸盐的制备

本文是作者在合成了一系列有机胂、有机(月弟)的钨、钼聚多酸盐后,有关若干有机膦合钼聚多酸“柄状”化合物的合成报导以及一些光学性质的测定。有关有机基团是C₂H₅,n-C₃H₇,n-C₄H₉,n-C₅H₁₁及C₆H₅CH₂。发现pH为3～5时,在不同的投料比例下都只形成一种类型的化合物[(RP)₂Mo₅O₂₁]^4-,与相应的有机胂衍生物既可形成[(RAs)₂Mo₅O₂₁]^4-又可形成[(RAs)₂Mo₆O₂₄]^4-有较大的差异。     

Bildung von Diphosphaten aus geschmolzenem Natriumtrimetaphosphat, 3. Mitt.

Zusammenfassung Beim Auflösen der Oxide von Ti(IV), Ni und Co in geschmolzenem Na₃P₃O₉ bilden sich die Diphosphate Na₂(TiO) P₂O₇, Na₂NiP₂O₇ und Na₂CoP₂O₇. Beim Auslaugen der erstarrten Schmelze mit Wasser tritt auch Na₂Co₃(P₂O₇)₂·4 H₂O auf; ein entsprechendes Hydrat wird auch bei Mn(II) gefunden. Außerdem bildet Mn (II) ein Polyphosphat [Mn (PO₃)₂] _n . — Beim Auflösen eines Gemisches aus SrO und PbO in wechselnden Mengenverhältnissen entstehen nebeneinander Mischkristalle von Na₂(Sr, Pb) P₂O₇ mit wechselndem Verhältnis Sr,Pb und von einem Ultraphosphat [(Sr, Pb) P₄O₁₁] _n mit dem konstanten Verhältnis Sr,Pb=0,66,0,34. — Die Polyphosphate von Mn und von Sr–Pb werden papierchromatographisch und IR-spektroskopisch untersucht. — Die Bildung von Diphosphaten aus einer Polyphosphatschmelze wird an Hand der hier und früher beschriebenen Befunde zu deuten versucht.

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On dissolving the oxides of Ti(IV), Ni or Co in molten Na₃P₃O₇ the diphosphates Na₂(TiO) P₂O₇, Na₂NiP₂O₇ and Na₂CoP₂O₇ are formed respectively. Mn(II) forms a polyphosphate [Mn(PO₃)₂] _n . On dissolving a mixture of SrO and PbO of varying ratio one obtains at the same time mixed crystals of Na₂(Sr,Pb)P₂O₇ with a variable ratio of Sr,Pb and an ultraphosphate [(Sr,Pb)P₄O₁₁] _n with a constant ratio Sr,Pb=0,66,0,34. An interpretation of the formation of diphosphates from a melt of polyphosphates is attempted, using the present and previous observations.

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Mit 1 Abbildung

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Herrn Prof. Dr.E. Hayek zum 60. Geburtstag gewidmet.     

Modeling of self-organization processes in crystal-forming systems. Structural mechanism of self-assembly of zirconosilicate Na2ZrSi2O7 from suprapolyhedral clusters

Topological analysis of the crystal structure of Na₂ZrSi₂O₇ (parakeldyshite, space group P1^–) with an MT framework, where M are ZrO₆ octahedra and T are SiO₄ tetrahedra, was carried out by the method of coordination sequences (TOPOS.3.2 program package), and the self-organization of this structure was modeled. The cyclic-type suprapolyhedral cluster precursor Na₂M₂T₄ with the local symmetry 1^– was identified by bicolor decomposition of the 4646+664 net. The cluster is composed of six polyhedra with two Na atoms located in the center. The precursors control the evolution of high-level crystal-forming clusters. The cluster coordination number is six. The centers of eight cluster precursors in the superprecursor of the Na₂ZrSi₂O₇ structure are related by translation vectors.     

Synthesis and crystal structure of a supramolecular adduct of trinuclear molybdenum oxocluster with macrocyclic cavitand cucurbit[5]uril containing the included ionic associate Na<Superscript>+</Superscript>...Cl...Na<Superscript>+</Superscript>

The compound of composition [{Mo₃O₄(H₂O)₆Cl₃}₂(Na₂Cl⊂ C₃₀H₃₀N ₂₀O₁₀)]Cl₃⋅14H₂O (1) was prepared by evaporation of a hydrochloric acid solution containing NaCl, the trinuclear aqua complex [Mo₃O₄(H₂O)₉]⁴⁺, and the macrocyclic cavitand cucurbit[5]uril (C₃₀H₃₀N₂₀O₁₀). X-ray diffraction analysis demonstrated that the cucurbit[5]uril molecule is closed on both sides by the cluster cations through hydrogen bonding between the CO groups of the cucurbit[5]uril portals and the aqua ligands of the oxo cluster. The inner cavity of the supramolecular adduct includes an unusual ionic associate Na⁺...Cl...Na⁺. The sodium cations are coordinated by five carbonyl oxygen atoms of each portal of the macrocycle. Compound 1 is the first structurally characterized complex, in which the macrocyclic cucurbit[5]uril ligand is directly coordinated to the alkali metal cation. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1513–1517, July, 2005.     

Na6(H2O)20(V10O28)·4H2O,a novel polyvanadate(V) with a three‐dimensional framework

The novel title polyvanadate(V), poly[[octa‐μ‐aqua‐dodecaaqua‐μ₄‐octacosaoxidodecavanadato‐hexasodium] tetrahydrate], [Na₆(H₂O)₂₀(V₁₀O₂₈)·4H₂O]_n, contains [V₁₀O₂₈]⁶⁻ anions which lie about inversion centres and have approximate 2/m symmetry and which are linked to [Na₃(H₂O)₁₀]³⁺ cations through two terminal and two μ₂‐bridging O atoms. The structure contains three inequivalent Na⁺ cations, two of which form [Na₂(H₂O)₈]_n chains, which are linked via NaO₆ octahedra involving the third Na⁺ ion, thus forming a three‐dimensional framework.     

Na2O-P2O5系晶体微结构形态的拉曼光谱研究及其ab initio计算

本文采用激光拉曼光谱仪测量了磷酸钠二元系(1-x)Na₂O·xP₂O₅(x=0.25,0.33,0.50,1.0)几种晶体的拉曼光谱,比较并解释了随化学组成而变化微结构单元的拉曼振动模。同时用Gaussian 98W量子化学软件从头计算了这几种化合物的拉曼光谱。实验和计算均表明,磷酸盐晶体的基本结构单元为磷氧四面体[PO₄],并且晶体中磷氧四面体的伸缩模振动频率与连接中心磷原子的桥氧数密切相关,随桥氧数增加而升高。此外还解释了模拟图谱与实验谱差异的原因。     

Sodium citrate dihydrate doped with Mn3+ ions

Sodium citrate dihydrate doped with Mn³⁺ ions, namely trisodium(I) managnese(III) citrate(3−) dihydrate, [Na₃Mn_0.011(C₆H₅O₇)(H₂O)₂]_n, was obtained during attempts to prepare some complex Mn^III citrates from a concentrated strong alkaline solution containing Na⁺, Mn³⁺ and citrate ions. The compound is isostructural with the recently described Na₃(C₆H₅O₇)·2H₂O [Fischer & Palladino (2003). Acta Cryst. E 59 , m1080–m1082]. The essential difference between these two structures is the presence of a very small proportion (0.205 wt%) of Mn³⁺ ions, which are positioned at the special 4e Wyckoff position in C2/c, where they are in a highly distorted octahedral environment of O atoms from two citrate anions.