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.     

Beiträge zur Chemie des Phosphors. 225 [1, 2] Lithium-pentahydrogenoctaphosphid

Contributions to the Chemistry of Phosphorus. 225. Lithium Pentahydrogen Octaphosphide Lithium pentahydrogen octaphosphide, LiH₅P₈ ( 1 ), belongs to the first reaction products of the metallation of P₂H₄ with n-butyllithium to be detected. Compound 1 is also formed in the reactions of the tricyclic heptaphosphide Li₃P₇ or the monocyclic pentaphosphide LiH₄P₅ with P₂H₄. In all cases, LiH₄P₇, LiH₈P₇, and further not yet identified polyphosphides are formed additionally. The composition and the structure of 1 have been elucidated by ³¹P-NMR studies, above all a complete analysis of its low-temperature ³¹P{¹H}-NMR spectrum. Hence, compound 1 is 7-lithium-2,5,6-trihydrogen-3-phosphino-bicyclo[2.2.1]heptaphosphide and has a norbornane-type P₇ skeleton. At room temperature 1 decomposes to furnish more phosphorus-rich lithium polyphosphides.     

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. 183. Lithium-tetrahydrogenheptaphosphid und Lithium-octa-hydrogenheptaphosphid

Contributions to the Chemistry of Phosphorus. 183. Lithium Tetrahydrogen Heptaphosphide and Lithium Octahydrogen Heptaphosphide Lithium tetrahydrogen heptaphosphide, LiH₄P₇ ( 1 ), and lithium octahydrogen heptaphosphide, LiH₈P₇ ( 2 ), belong to the first reaction products of the metalation of P₂H₄ with n-butyllithium that can be identified. Both compounds are also formed on reaction of Li₃P₇ with excess P₂H₄. 1 also results from the reaction of LiH₄P₅ with P₂H₄. Whereas 1 can be isolated as an orange-red crystalline solvent adduct in a purity of 60-70 per cent, 2 cannot be enriched further due to its extreme reactivity. The composition and the structure of 1 and 2 have been elucidated from their ³¹P-NMR spectra. Hence, 1 has a P₇ skeleton analogous to that of norbornane, whereas 2 as a precursor in the formation of 1 from P₂H₄ and n-BuLi is an open-chain doubly branched heptaphosphide.     

Darstellung und Kristallstruktur des Lithium‐Strontium‐Hydridnitrids LiSr2H2N

Synthesis and Crystal Structure of the Lithium Strontium Hydride Nitride LiSr₂H₂N LiSr₂H₂N was synthesized by the reaction of LiH and Li₃N with elemental strontium in sealed tantalum tubes at 650 °C within seven days. This second example of a quaternary hydride nitride crystallizes orthorhombically in space group Pnma (no. 62) with the lattice constants a = 747.14(5) pm, b = 370.28(3) pm and c = 1329.86(9) pm (Z = 4). Its crystal structure contains both kinds of anions H^? and N^3? in a sixfold distorted octahedral metal cation coordination each. The coordination polyhedra [(H1)Sr₅Li]¹⁰⁺, trans‐[(H2)Sr₄Li₂]⁹⁺ and [NSr₅Li]⁸⁺ are connected via edges and corners to form a three‐dimensional network. Two crystallographically different Sr²⁺ cations exhibit a sevenfold monocapped trigonal prismatic coordination by H^? and N^3? with [(Sr1)H₅N₂]^9? and [(Sr2)H₄N₃]^11? polyhedra, wheras Li⁺ shows a nearly planar fourfold coordinative environment ([LiH₃N]^5?). Cationic double chains of edge‐shared [NSr₅Li]⁸⁺ octahedra dominate the structure according to . Running parallel to the [0 1 0] direction, they are bundled like a hexagonal rod‐packing which is interconnected by H^? anions within the (0 0 1) plane first and finally even in the third dimension (i. e. along [0 0 1]). Therefore the structure of LiSr₂H₂N is compared to that one of the closely related quaternary hydride oxide LiLa₂HO₃.     

Wellenmechanische Absolutrechnungen an Molekülen und Atomsystemen mit der SCF?MO?LC(LCGO) Methode. VII. Das System (LiH2)−

The system (LiH₂)^? has been investigated for several nuclear positions, taking all six electrons into account, using the Allgemeines Programmsystem/SCF ? MO ? LC (LCGO ) Methode. A metastable molecule was found having a linear configuration (R_LiH = 3.5 ± 0.2 a.u.) and a total energy 0.12 a.u. lower than that of the separated atoms. On the other hand, (LiH₂)^? can dissociate into Li^? + H₂; the total energy of which is 0.01 a.u. smaller. The potential barrier for this process is found to be 0.15 a.u. The energy hypersurface is given graphically and the formation (as well as the decomposition) of (LiH₂)^? is discussed.     

Beiträge zur Chemie des Phosphors. 143. Li4P26 und Na4P26, die ersten Salze mit Hexacosaphosphid(4−)-Ionen

Contributions to the Chemistry of Phosphorus. 143. Li₄P₂₆ and Na₄P₂₆, the First Salts with Hexacosaphosphid(4?) Ions The hexacosaphosphides Li₄P₂₆ ( 1 ) and Na₄P₂₆ ( 2 ) are formed besides other polyphosphides in the reaction of white phosphorus with lithium dihydrogenphosphide or sodium. 1 also results from the decomposition of Li₂HP₇ in tetrahydrofuran at room temperature and can be obtained pure as a crystalline solvent adduct Li₄P₂₆ · 16 THF. According to 2D?³¹P-NMR spectroscopic investigations the P₂₆^4? ion is a conjucto-phosphane of two P₇(5)^?-and two P₉(3)^?-unit groups with structures analogous to norbornane and deltacyclane, respectively.     

Theoretical study of one‐electron bonds in a series of high‐spin lithium–beryllium–hydrogen clusters: “Valence shell single‐electron repulsion” rule and electron localization function analysis

A series of high‐spin clusters containing Li, H, and Be in which the valence shell molecular orbitals (MOs) are occupied by a single electron has been characterized using ab initio and density functional theory (DFT) calculations. A first type (⁵Li₂, ⁿ⁺¹LiH_n+ (n = 2–5), ⁸Li₂H) possesses only one electron pair in the lowest MO, with bond energies of ～3 kcal/mol. In a second type, all the MOs are singly occupied, which results in highly excited species that nevertheless constitute a marked minimum on their potential energy surface (PES). Thus, it is possible to design a larger panel of structures (⁸LiBe, ⁷Li₂, ⁸Li, ⁴LiH⁺, ⁶BeH, ⁿ⁺³LiH (n = 3, 4), ⁿ⁺²LiH (n = 4–6), ⁸Li₂H, ⁹Li₂H, ²²Li₃Be₃ and ²²Li₆H), single‐electron equivalent to doublet “classical” molecules ranging from CO to C₆H₆. The geometrical structure is studied in relation to the valence shell single‐electron repulsion (VSEPR) theory and the electron localization function (ELF) is analyzed, revealing a striking similarity with the corresponding structure having paired electrons. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

All-solid-state batteries with Li2O-Li2S-P2S5 glass electrolytes synthesized by two-step mechanical milling

Sulfide solid electrolytes, which show high ion conductivity, are anticipated for use as electrolyte materials for all-solid-state batteries. One drawback of sulfide solid electrolytes is their low chemical stability in air. They are hydrolyzed by moisture and generate H₂S gas. Substituting oxygen atoms for sulfur atoms in sulfide solid electrolytes is effective for suppression of H₂S gas generation in air. Especially, the xLi₂O·(75-x)Li₂S·25P₂S₅ (mol%) glasses hardly generated H₂S gas in air. However, substituting oxygen atoms for sulfur atoms caused a decrease in conductivity. The x?=?7 glass showed high chemical stability in air and maintained high conductivity of 2.5?×?10^?4 S cm^?1 at room temperature. Performance of cells using the 7Li₂O·68Li₂S·25P₂S₅ and the 75Li₂S·25P₂S₅ glasses as solid electrolytes were compared. All-solid-state C/LiCoO₂ cell using the 7Li₂O·68Li₂S·25P₂S₅ glass produced performance as good as that obtained using the 75Li₂S·25P₂S₅ glass. Capacity retention and change of interfacial resistance of the former cell were superior to those of the latter cell after storage at 4.0 V and 60 °C. The diffusion of oxygen element into the 7Li₂O·68Li₂S·25P₂S₅ glass was less than that into the 75Li₂S·25P₂S₅ glass after storage at the voltage of 4.0 V at 60 °C. Improvement of the stability of sulfide solid electrolytes to moisture was related to cell performance as well as an increase in conductivity.     

Competitive Coordination of the Uranyl ion by Perchlorate and Water – The Crystal Structures of UO2(ClO4)2·3H2O and UO2(ClO4)2·5H2O and a Redetermination of UO2(ClO4)2·7H2O (Z. Anorg. Allg. Chem. 2003, 629, 1012–1016)

In the article “Competitive Coordination of the Uranyl ion by Perchlorate and Water – The Crystal Structures of UO₂(ClO₄)₂·3H₂O and UO₂(ClO₄)₂·5H₂O and a Redetermination of UO₂(ClO₄)₂·7H₂O” (Z. Anorg. Allg. Chem. 2003 , 629, 1012–1016), some wrong parameters and bond lengths for UO₂(ClO₄)₂·7H₂O were given in table 1 and table 3 The correct parameters are: a = 1449.5(2) pm, b = 921.6(1) pm, c = 1067.5(2) pm, V = 1422.5(4)·10⁶ pm³, ρ = 2.712 g·cm^?3, μ = 119 cm^?1. The corrected bond lengths for this structure are U–O(1) 175.8(5) pm, U–O(2) 239.1(5) pm, U–O(3) 240.8(5), U–O(4) 242.0(7). A cif file with the correct data has been deposited with the ICSD.     

Zur thermischen Dehydratisierung von Lithiumdihydrogenphosphat, -hydrogendiphosphat und -cyclophosphat-Hydraten

Thermal Dehydration of Lithium Dihydrogenphosphate, -Hydrogen-diphosphate, and -Cyclophosphate Hydrates On heating lithium dihydrogenphosphate, LiH₂PO₄, is converted to lithium polyphosphate, (LiPO₃)_n · H₂O [2–5]. Seeding LiH₂PO₄ with lithium cyclohexaphosphate, Li₆P₆O₁₈, the thermal dehydration proceeds structurally controlled to pure Li₆P₆O₁₈. On heating lithium hydrogen-diphosphate, Li₃HP₂O₇, reacts to Li₄P₂O₇ form III and lithium cyclotetraphosphate, Li₄P₄O₁₂ form II , which ist converted to Li₆P₆O₁₈ at higher temperatures. The thermal dehydration of Li₂H₂P₂O₇ and of the cyclophosphate hydrates Li₃P₃O₉ · 3 H₂O, Li₄P₄O₁₂ · (8 and 6) H₂O, Li₆P₆O₁₈ · (6 and 4) H₂O and Li₈P₈O₂₄ · (10 and 6) H₂O are described.     

Wellenmechanische Absolutrechnungen an Molekülen und Atomsystemen mit der SCF?MO?LC(LCGO) Methode. VIII. Das System (Li2H)+

The (Li₂H)⁺ has been investigated ab initio in the linear configuration, with the H atom in the middle of the system, for five different distances R_LiH, taking all six electrons into account, using the Allgemeines Programmsystem/SCF? MO? LC(LCGO) Verfahren. A bond distance R_LiH of 3.14 a.u., a total energy of ?15.289 a.u., and an ionization energy of 15.1 eV were found. Comparing the results of SCF investigations, the formation energy of (Li₂H)⁺ from LiH and Li⁺ was computed to be 59.7 kcal/mole (2.58 eV). Using the energy curve near the minimum, a force constant for the symmetric vibration of k = 0.13777 × 10⁶ dyn/cm and a frequency ω = 577.9 cm^?1 were found.     

Nuclease activity of redox/non-redox active binuclear transition metal mixed-polypyridine complexes: [M2(1,4-tpbd)(diimine)2(H2O)2]4+, M = Zn,Co, Ni,Cd, diimine = phen,bpy, dafo

Seven new transition metal complexes formulated as [M₂(1,4-tpbd)(diimine)₂(H₂O)₂]⁴⁺ [M = Zn, Co, Ni, Cd; 1,4-tpbd = N,N,N′,N′-tetrakis(2-pyridylmethyl)benzene-1,4-diamine; diimine is a N,N-donor heterocyclic base like 1,10-phenanthroline (phen), 2,2′-bipyridine (bpy), 4,5-diazafluoren-9-one (dafo)] have been synthesized and structurally characterized by X-ray crystallography: [Zn₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (1), [Zn₂(1,4-tpbd)(bpy)₂(H₂O)₂]⁴⁺ (2), [Co₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (3), [Ni₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (4), [Ni₂(1,4-tpbd)(bpy)₂(H₂O)₂]⁴⁺ (5), [Ni₂(1,4-tpbd)(dafo)₂(H₂O)₂]⁴⁺ (6) and [Cd₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (7). Single crystal diffraction reveals that the metals in the complexes are all in a distorted octahedral geometry. The interactions of the seven complexes with calf thymus DNA (CT-DNA) have been investigated by UV absorption, fluorescence, circular dichroism spectroscopy and viscosity measurements. The apparent binding constants (K_app) are calculated to be 5.2?×?10⁵ M^?1 for 1, 1.05?×?10⁵ M^?1 for 2, 5.76?×?10⁵ M^?1 for 3, 4.57?×?10⁵ M^?1 for 4, 1.29?×?10⁵ M^?1 for 5, 1.7?×?10⁵ M^?1 for 6, 2.53?×?10⁵ M^?1 for 7, the binding propensity to the calf thymus DNA in the order: 3 (Co-phen) > 1 (Zn-phen) > 4 (Ni-phen) > 7 (Cd-phen) > 6 (Ni-dafo) > 5 (Ni-bpy) > 2 (Zn-bpy). Furthermore, these complexes display efficient oxidative cleavage of supercoiled DNA; the Zn(II)/H₂O₂ and Cd(II)/H₂O₂ systems efficiently cleave DNA attributed to the peroxide ion coordinated to the Zn(II) and Cd(II), which enhanced their nucleophilicity, this is rare.     

Chemie polyfunktioneller Moleküle. 119 [1] Tetracarbonyl-dicobalt-tetrahedran-Komplexe mit den Liganden Bis(diphenyl-phosphanyl)amin, 2-Butin-1,4-diol und tert-Butylphosphaacetylen — Kristallstrukturanalyse des Phosphaalkin-Derivats

Chemistry of Polyfunctional Molecules. 119 [1]. Tetracarbonyl-dicobalt-tetrahedrane Complexes with the Ligands Bis(diphenylphosphanyl)-amine, 2-Butin-1,4-diol, and tert.-Butylphosphaacetylene — Crystal Structure of the Phosphaalkyne Derivative Co₂(μ-CO)₂(CO)₄(μ-Ph₂P? NH? PPh₂—P,P′) · 1/2C₆H₅CH₃ ( 4 · 1/2C₆H₅CH₃) reacts with 2-butine-1,4-diol, HOCH₂? C?C? CH₂OH ( 5 ), to the dark-red tetrahedrane complex Co₂(CO)₄(μ-η²,η²-HOCH₂? C?C? CH₂OH? C², C³) · (μ-Ph₂P? NH? PPh₂? P,P′) · THF (6 · THF). With t-butyl-phosphaacetylene, tBu? C?P ( 7 ), 4 · THF forms Co₂(CO)₄(μ-η²,η²-tBu? C?P)(μ-Ph₂P? NH? PPh₂? P,P′) ( 8 ), which also belongs to the tetrahydrane type. The compounds were characterized by their mass, IR, ³¹P{¹H} NMR, ¹³C{¹H} NMR, and¹H NMR spectra. Crystals suitable for X-ray structure analyses have been obtained for 8 from dioxane. The dark red blocks crystallize in the monoclinic P2₁/c space group with the lattice constants a = 1404,1(5), b = 1330,0(7), c = 2578,8(10)pm; β = 90,82(3)°.     

Li+ cation coordination in [Li2(CF3SO3)2(diglyme)] and [Li3(C2F3O2)3(diglyme)]

The title compounds, poly­[[[bis(2‐methoxy­ethyl) ether]­lithium(I)]‐di‐μ₃‐tri­fluoro­methanesulfonato‐lithium(I)], [Li₂(CF₃SO₃)₂(C₆H₁₄O₃)]_n, and poly­[[[bis(2‐methoxy­ethyl) ether]­lithium(I)]‐di‐μ₃‐tri­fluoro­acetato‐dilithium(I)‐μ₃‐tri­fluoro­acetato], [Li₃(C₂F₃O₂)₃(C₆H₁₄O₃)]_n, consist of one‐dimensional polymer chains. Both structures contain five‐coordinate Li⁺ cations coordinated by a tridentate diglyme [bis(2‐methoxy­ethyl) ether] mol­ecule and two O atoms, each from separate anions. In both structures, the [Li(diglyme)X₂]^? (X is CF₃SO₃ or CF₃CO₂) fragments are further connected by other Li⁺ cations and anions, creating one‐dimensional chains. These connecting Li⁺ cations are coordinated by four separate anions in both compounds. The CF₃SO₃^? and CF₃CO₂^? anions, however, adopt different forms of cation coordination, resulting in differences in the connectivity of the structures and solvate stoichiometries.     

Studies of layered uranium (VI) compounds. VI. Ionic conductivities and thermal stabilities of MUO2PO4 · nH2O,where M = H,Li,Na,K,NH4 or 12Ca, and where n is between 0 and 4

We have measured the ionic conductivities of pressed pellets of the layered compounds MUO₂PO₄ · nH₂O, and correlated the results with TGA data. The conductivities (in ohm^?1 m^?1), at temperatures increasing with decreasing water content over the range 20 to 200°C, were approximately as follows: Li⁺4H₂O, 10^?4; Li⁺, Na⁺, K⁺, and NH₄⁺3H₂O, 10^?4, 10^?2, 10^?4, and 10^?4; H⁺, Li⁺, and Na⁺1.5H₂O, 10^?2, 10^?4, and 10^?4; Na⁺1H₂O, 10^?5; H⁺, K⁺, and NH₄⁺0.5H₂O, all 10^?5; and H⁺, Li⁺, Na⁺, K⁺, NH⁺₄, and $\text{1}\text{2}\text{Ca}{}^{\mathrm{2+}}\text{}\text{OH}{}_2\text{O}$, 10^?5, 10^?5, 10^?4, 10^?5, 10^?5, and 10^?6. A ring mechanism is proposed to account for the high conductivity found in NaUO₂PO₄ · 3.1H₂O. The accurate TGA data showed that most of the hydrates had water vacancies of the Schottky type, and should be represented as MUO₂PO₄(A ? x)H₂O, where x can be between 0 and 0.3.     

Thermochemical Study on [La(Hsal)2•(tch)]•2H2O [Hsal＝salicylate ( ), tch＝thioprolinate (C4H6NO2S-)]

The product from reaction of lanthanum chloride heptahydrate with salicylic acid and thioproline, [La(Hsal)2•(tch)]•2H2O, was synthesized and characterized by IR, elemental analysis, molar conductance, thermogravimatric analysis and chemistry analysis. The standard molar enthalpies of solution of LaCl3•7H2O (s), [2C7H6O3 (s)], C4H7NO2S (s) and [La(Hsal)2•(tch)]•2H2O (s) in a mixed solvent of absolute ethyl alcohol, dimethyl sulfoxide (DMSO) and 3 mol•L－1 HCl were determined by calorimetry to be [LaCl3•7H2O (s), 298.15 K]＝(－102.36±0.66) kJ•mol－1, [2C7H6O3 (s), 298.15 K]＝(26.65±0.22) kJ•mol－1, [C4H7NO2S (s), 298.15 K]＝(－21.79±0.35) kJ•mol－1 and {[La(Hsal)2•(tch)]•2H2O (s), 298.15 K}＝(－41.10±0.32) kJ•mol－1. The enthalpy change of the reaction LaCl3•7H2O (s)＋2C7H6O3 (s)＋C4H7NO2S (s)＝[La(Hsal)2•(tch)]•2H2O (s)＋3HCl (g)＋5H2O (l) (Eq. 1) was determined to be ＝(41.02±0.85) kJ•mol－1. From date in the literature, through Hess’ law, the standard molar enthalpy of formation of [La(Hsal)2•(tch)]•2H2O (s) was estimated to be {[La(Hsal)2•(tch)]•2H2O (s), 298.15 K}＝(－3017.0±3.7) kJ•mol－1.     

Lithium and beryllium hypophosphites

The structures of monoclinic (C2/m) lithium di­hydrogenphosphate, LiH₂PO₂, and tetragonal (P4₁2₁2) beryllium bis(di­hydrogenphosphate), Be(H₂PO₂)₂, have been determined by single‐crystal X‐ray diffraction. The structures consist of layers of hypophosphite anions and metal cations in tetrahedral coordination by O atoms. Within the layers, the anions bridge four Li⁺ and two Be²⁺ cations, respectively. In LiH₂PO₂, the Li atom lies on a twofold axis and the H₂PO₂⁻ anion has the PO₂ atoms on a mirror plane. In Be(H₂PO₂)₂, the Be atom lies on a twofold axis and the H₂PO₂⁻ anion is in a general position.     

Synthesis and Crystal Structure of Lithium Tetrametaphosphimate Tetrahydrate Li4(PO2NH)4 · 4 H2O

Single crystals of Li₄(PO₂NH)₄ · 4 H₂O were obtained by dissolving LiOH and H₄(PO₂NH)₄ · 2 H₂O in water and subsequent precipitation with acetone and ethanol followed by slow evaporation of the solvents. The structure of Li₄(PO₂NH)₄ · 4 H₂O was solved by single‐crystal X‐ray methods ( (No. 2), a = 489.2(2), b = 853.2(2), c = 880.5(2) pm, α = 101.71(3), β = 102.39(3), γ = 94.88(3)°, Z = 1). The structure is composed of LiO₄ tetrahedra and (PO₂NH)₄^4? ions. The P₄N₄ rings of the anions exhibit a slightly distorted chair–1 conformation, which is supported by IR data and has been described by torsion angles, displacement asymmetry parameters and puckering parameters. Via Li⁺ ions and hydrogen bonds, the tetrametaphosphimate anions are connected forming a three‐dimensional network.     

Isopiestic Determination of the Osmotic and Activity Coefficients of Li2SO4(aq) at T=298.15 and 323.15 K, and Representation with an Extended Ion-Interaction (Pitzer) Model

Isopiestic vapor-pressure measurements were made for Li₂SO₄(aq) from 0.1069 to 2.8190 mol?kg^?1 at 298.15 K, and from 0.1148 to 2.7969 mol?kg^?1 at 323.15 K, with NaCl(aq) as the reference standard. Published thermodynamic data for this system were reviewed, recalculated for consistency, and critically assessed. The present results and the more reliable published results were used to evaluate the parameters of an extended version of Pitzer’s ion-interaction model with an ionic-strength dependent third-virial coefficient, as well as those of the standard Pitzer model, for the osmotic and activity coefficients at both temperatures. Published enthalpies of dilution at 298.15 K were also analyzed to yield the parameters of the ion-interaction models for the relative apparent molar enthalpies of dilution. The resulting models at 298.15 K are valid to the saturated solution molality of the thermodynamically stable phase Li₂SO₄?H₂O(cr). Solubilities of Li₂SO₄?H₂O(cr) at 298.15 K were assessed and the selected value of m(sat.)=3.13±0.04 mol?kg^?1 was used to evaluate the thermodynamic solubility product K _s(Li₂SO₄?H₂O, cr, 298.15 K) = (2.62±0.19) and a CODATA-compatible standard molar Gibbs energy of formation Δ_f G _m ^o (Li₂SO₄?H₂O, cr, 298.15 K) = ?(1564.6±0.5) kJ?mol^?1.