In oxide glasses, strongly hydrogen-bonded protons which give IR absorption band at around 2900 cm^-1 are very mobile, while hydrogen-bonding free protons which give its band at around 3600 cm^-1 are immobile or much less mobile. The mobilities of protons increase with the strength of the hydrogen bonding. The superprotonic conductors of oxide glasses are developed for the phosphate glasses containing a large amount of mobile protons and molecular water. The theories of potential development of pH-glass electrodes which are long pending problem are discussed in terms of the mobile protons of the glasses. We assert that the presence of the mobile protons is indispensable for its pH-response.

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Phosphate (P) and fluoride phosphate (FP) glasses are attractive materials for a wide range of photonic applications such as lasers, amplifiers, photosensitivity, optical storage and Faraday rotators. They demonstrate high UV transmission, low linear and nonlinear refractive index, low viscosity and low melting temperatures, athermal behaviour. In addition, they are excellent host materials for active rare earth (RE) ions due to advantageous local structure effect and high RE ion solubility. The paper reviews the benefit of FP and P glass properties for different photonic applications. Base glass properties, local structure and its effect on RE ion properties are described for FP and P glasses studied by the author. The potential of the glasses for laser, amplifier and photosensitivity-based devices are demonstrated.

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Triton X-100, water-soluble but non-adsorbable to HAP, was adsorbed after formation of a mixed hemimicelle together with SDS. Water-insoluble dye, MY, was incorporated into an SDS aggregate formed on the surface in a similar manner to that of ordinary solubilization performed in an aqueous phase. Water-soluble polymer HPC formed a surface complex of SDS-HPC, which bridged among HAP particles, resulting in flocculation of the particles. Water-soluble MO was captured by BSA adsorbed on HAP, resulting in an increase in its amount of adsorption on the surface of HAP. Mono- and dialkylphosphate was adsorbed to HAP in a similar manner to that of SDS, i.e., after isomorphous substitution. Understanding these phenomena is important for understanding mechanisms of the interaction between drugs and hard tissues and the absorption of drugs into hard tissues as well as the formation of animal hard tissues composed of HAP and organic compounds.

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In order to gain better understanding of the interaction between apatite and organic species in engineered and/or biological, systems, we have studied the effects of four organic ligands, acetate, malonate, citrate and EDTA, on the supersaturation, with respect to calcium and phosphate, required for the onset of precipitation in aqueous solutions at pH 7, 25°C and 0.1M ionic strength. Organic ligands may influence both the supersaturation in solution and the crystallinity of the precipitating (hydroxyl)apatite. The ligands with two or more carboxyl groups appear to cause an increase in the supersaturation required for precipitation, and this is interpreted as an inhibitory effect by these ligands. Citrate is the most efficient inhibitor.

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With regard to fragility and workability, the calcium metaphosphate-like melt (CMP) with the composition 51.4Ca0 48.6P₂0₅ in mol%is compared with the soda-lime-silicate melt (NCS) with the composition 16Na₂O-10CaO-74SiO₂ in mol%. The fragility of the two melts is characterised by determining the fragility index F_1/2, the difference in heat capacity between glass and melt, and configurational entropy. The difference of heat capacity between the CMP glass and crystal is measured. The intense crystallisation takes place at the temperature T=1.20T_g, where T_g is the glass transition temperature. The fibres are drawn from the CMP melt. The ratio of the fictive temperature T_f to T_g of these fibres is found to be 1.053 by estimating the excess energy stored during fibre forming. Relaxation features of the CMP fibres are examined by doing systematic thermal ageing experiments and calorimetric measurements. The endotherm and exotherm simultaneously occur in a certain range of ageing temperatures. The dependence of the endotherm and extherms on the ageing temperature is discussed.

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The influence of polymer architecture on the precipitation of amorphous calcium phosphate from supersaturated solutions has been investigated using the pH-stat technique. It has been found that low concentration of acrylic acid based copolymers and terpolymers markedly inhibit the precipitation of calcium phosphate. Homopolymers containing anionic, non-ionic, and cationic groups under similar experimental conditions are inefficient as calcium phosphate inhibitors. The inhibition data of several polymers indicate that the performance of polymers depends upon the functional group, ionic charge, and the molecular weight. In addition, it has been found that cationic flocculants and biocides when present at low concentrations exhibit strong antagonistic effect on the performance of calcium phosphate inhibiting polymers.

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The precipitation of calcium phosphonates in the presence of a variety of anionic polymers has been investigated. The inhibition data show that polymer effectiveness as calcium phosphonate inhibitor strongly depends upon polymer architecture. The results also indicate that performance of polymers is strongly influenced by low concentrations of cationic additives such as polymeric floccualants, coagulants, and biocides.

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Na₂O-Al₂O₃-P₂O₅ and Na₂O-K₂O-Al₂O₃-Ga₂O₃-P₂O₅ glasses were investigated with Rayleigh and Mandel'shtam-Brillouin scattering (RMBS) spectroscopy and high temperature ultrasonic study (HTUS). RMBS spectra intensities, their ratios and spectral shifts were determined as functions of glass compositions. Using the model of “freezing” of concentration, density, and anisotropy fluctuations in the process of cooling of a glass forming melt it was found that Rayleigh scattering losses are presumably a function of chemical microinhomogeneity of phosphate glasses. Low-scattering glass compositions were found.

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Low melting zinc metaphosphate glasses (ZnO:P₂O₅=1:1, SiO₂ 8-12, Al₂O₃ 2-8 mol.%) for thick-film resistors (TFR) have been investigated.
A polymeric chain of investigated glasses is made up of PO₄ adjacent tetrahedra connected at two corners upon bridging oxygens, so that there are two non-bridging oxygen atoms on each tetrahedron. With modifier ion Zn silica-like network is realised.
Following properties of glasses were studied: thermal expansion coefficient, transformation and softening temperatures, chemical durability, density, electrical resistivity depending on temperature and presence of crystalline phases. Viscosity as a function of the temperature (740÷1120°C) of the glass melts depends on the content of Al₂O₃.
Values of viscosity of glasses containing Al₂O₃ 5≤6mol.%, at the firing temperature (about 850°C) for TFR on alumina substrate (96% Al₂O₃) are 10 ^2,1÷10 ^2,6 Pa. s; Eη-152÷163 kJ/mol.
Owing to the suitable thermal, electrical properties and viscosity, the zinc metaphosphate glasses could be applied in production of TFR on RuO₂ basis.

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Chemical durability of the glass 0.8 LiF - 0.2 Al(PO₃)₃ (designated below as LiF-80) was studied in water and in 0.01 mol dm^-3 HCl solution (further 0.01 M). The experiments were carried out at 25, 40 and 60°C with glass discs in unstirred solutions, which have been refreshed daily during a month. The methods used were mass loss measurements and determination of Li, F, and P₂O₅ concentrations in the solutions. The mean velocities and the apparent activation energies of the glass dissolution were estimated. The time dependencies of mass losses and leaching of the components were apparently linear. The ratios Li F and Li / P₂O₅ in solutions tend to be twice in water and four times as large in HCl solution in comparison to such ratios in glass itself, i.e. the dissolution of the glass runs with a preferred leaching of Li⁺. Additions of 2 and 5% CaO (over 100% by weight) increase slightly the chemical durability of the glass in unstirred 0.1 M HCl solution. In comparison with the glass LiF-80 the durability of the glass LiF-85 is much worse.

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Microcrystalline powders of acid diphosphates M₂(H₂P₂O₇)₂ (M = Co, Ni, Zn) deposit from solutions of the metals in half-concentrated H₃PO₄ (nM : nP~1: 100) at T = 70°C. Yellowish single crystals of Ni₂(H₂P₂O₇)₂ suitable for X-ray investigations have been obtained in reactions under hydrothermal conditions (V_Amp.~2.5 mL, T~400°C, 100 mg NiO, 125 mg P₄O₁₀, 1 mL conc. H₃PO₄). The crystal structure of Ni₂(H₂P₂O₇)₂ (P2₁/c, Z = 4, 20 non-hydrogen atoms in the asymmetric unit, 2 of 4 hydrogen atoms located from Δ-Fourier synthesis, R1 = 0.027 for 1696 F_o > 4σ(F_o), wR2 = 0.067, 2530 reflections, 190 parameters) consists of infinite chains of edge-sharing [NiO₆] octahedra and [H₂P₂O₇] units. Two diphosphate groups are linked by hydrogen bridges, thus building an arrangement similar to a cyclo-tetrametaphosphate. A second type of hydrogen bridges is suggested to connect these rings to a 3-dimensional network. Between the structures of the M₂(H₂P₂O₇)₂ and anhydrous cyclo-tetrametaphosphates M₂P₄O₁₂ a remarkably close relation is observed, suggesting a topotactic mechanism for the dehydration reaction. Actually, upon heating of Zn₂(H₂P₂O₇)₂ to 400°C Zn₂P₄O₁₂, which is metastable with respect to Zn(PO₃)₂, is formed instead of the long-chain metaphosphate. The acid diphosphates Mg₂(H₂P₂O₇)₂ and Zn₂(H₂P₂O₇)₂ reported in the powder diffraction file are isotypic to Ni₂(H₂P₂O₇)₂.

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Spectroscopic properties of Eu³⁺ in the fluorophosphate glases are described. Fluorescence, IR absorption, Rayleigh and Mandel'shtam-Brillouin scattering spectra, decay time dependencies have been obtained. Interpretation is carried out in terms of selective occupying sites with different environment in glass host by Eu³⁺ -ions.

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The results of EPR study of phosphate glasses of the system CaO- P₂O₅ implanted with Cr⁺, V⁺ and ⁹⁵ Mo⁺ are reported. It is shown that Cr³⁺,V⁴⁺ and Mo⁵⁺ can present in implantation layer in their typical isolated states depending on glass composition and implantation conditions. It was found that at high implantation doses ferromagnetic compound CrO₂ and crystal VO₂ are formed.

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Rare earth phosphate glasses with molar compositions xRE₂O₃ (1-x)P₂O₅ (0≤x0.30) were prepared and characterized by extended x-ray absorption fine structure (EXAFS) spectroscopy and by high-energy x-ray diffraction (XRD) analyses. The analyses indicate that the average coordination number (CN) of the RE³⁺ ions depends on composition: ultraphosphate glasses with less than -15 mole% RE₂O₃ have average RE CN's of 8-9 and CN decreases to -6 with increasing RE₂O₃ content to 25 mole%. The compositional dependence of RE CN can be understood with a simple model in which the formation of structurally isolated RE-polyhedra is favored in ultraphosphate glasses. Glass properties, including refractive index and glass transition temperature, are sensitive to changes in glass structure.

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One dimensional ¹⁷O MAS NMR along with multiple quantum MAS NMR has been used to identify at least three different oxygen sites, including the bridging oxygens (BO) and two different terminal oxygens (TO), in the hexagonal (h) crystalline form of P₂¹⁷O₅. The ¹⁷ O MAS NMR spectrum from v-P₂¹⁷O₅ reveals that a distribution of oxygen environments are present, such that the BO and TO are not resolvable under simple MAS.

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The solid electrolyte powders of Li_1+x+y Sc_xB_yTi_2-x-y(PO₄)₃ (where x, y=0, 0.1, 0.2, 0.3) were synthesized by solid state reaction. The structure of all compounds was studied by X-ray diffraction from the powder. The ionic conductivity of the sintered ceramic samples has been investigated by impedance spectroscopy in the frequency range from 7·10⁵ to 1.2·.10⁹ Hz at temperatures up to 600 K. Two relaxation dispersions of the electrical parameters were found and analyzed in terms of bulk and grain boundary ionic transport processes

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A high strength glass-ceramic of the system MgO-TiO₂-P₂O₅-Al₂O₃-SiO₂ was modified on the surface, by an ion exchange with an eutectic salt melt (CaCl₂/CaF₂) or a modified salt melt (CaCl₂/CaF₂/Ca(PO₃)₂) of the base glass. The surfaces of the samples were investigated by means of optical and scanning electron microscopy, X-ray diffraction as well as IR spectroscopy. The formation of apatite crystals of different shape was observed in the surface layer of ion exchanged and subsequent thermal treated glass-ceramics.

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In industrial application, the polyphosphate coacervates present some interest for coating metallic pieces. To explain the good mechanical properties of this coating with some metal's substrate, we have studied the interface. To obtain a good coating we have to form layer rich in phosphide near the metal bulk. This layer stops the metal diffusion in the glass coating. For metal, like iron, which may present a formation of an important layer of oxides during the curing step, it is necessary to lay down a thin layer of reducible metal like aluminum on the substrate.

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In order to prepare an inorganic antimicrobial agent with a biocompatibility, we have attempted synthesis of beta-tricalcium phosphate(β-TCP) doped with silver using a solid-state reaction method, and have investigated the solubility and the bactericidal activity to Escherichia coli or Staphylococcus aureus of the obtained products. TCP solid solutions were formed by reaction of the mixture of β-TCP and silver ion. The Ca²⁺ ion in β-TCP was replaced with silver ion of up to 10 mol%. It was considered that Ca²⁺ ion and vacancy located Ca(4) site in β-TCP structure were displaced by two silver ions. The products doped with silver ion showed a high bactericidal activity and their antimicrobial effects increased with increase of the amount of silver ion. In order to change the bactericidal activity of a TCP doped with silver ion, further more, alkali metal ion was added to β-TCP together with silver ion. As the result, alkali metal ion also replaced Ca²⁺ ion, and formed the substituted solid solution that is similar to silver ion. The bactericidal activity of β-TCP doped with silver and potassium ions was increased and that of β-TCP doped with silver and lithium ions was decreased. This depended on the solubility of the obtained β-TCP solid solution. By means of ESR evaluation using a spin-trap reagent, we found that superoxide radicals was generated from β-TCP doped with silver ion by UV irradiation, and considered that β-TCP doped with silver ion has both an antimicrobial effect that was generated by photo irradiation and an antimicrobial effect that was caused by the dissolved silver ion.

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Ultraphosphate glasses in the system CuO-P₂O₅ were prepared from 0 to 18 mol% CuO (synthesis) starting from powdery P₄O₁₀ (p. a. Merck) and fresh prepared Cu₂P₄O₁₂ in closed SiO₂ glass ampoules between 1000° and 1100°C for about 2 hours. After cooling with about 10 K min^-1, the ampoules were stored under paraffin oil in a desiccator and handled with exclusion of “water”. Measurements of density, chemical composition, optical and infrared spectroscopy followed. The optical spectra only show Cu²⁺, but in different positions, depending on CuO content. Cu⁺ was not found, although the glasses were melted without air contact. The different places of the copper ions in the glass structure are connected with the structure change: With increasing content of copper more Q² linked {PO₄} tetrahedra were built. This finding strongly agrees with the infrared spectra, which show an increase of Q²{PO₄} tetrahedra with increasing CuO content. The structure evolution seems to follow a binary distribution model: the (P₂O₅)_x specific substructure units decrease, where the CuP₄O₁₁ specific substructure units increase while the CuO content increases.

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The transitional point in phosphate glasses between a surfeit of terminal oxygen atoms and a situation where modifier ions share oxygen neighbors in their coordination polyhedra depends on the valency and dimension of the Me added. For polyphosphate glasses with the small Ga³⁺ cations the transition is still not at-tained (decrease of N_Gao) while for the glasses with Y, Mg, Zn with constant N_MeO the transition is already passed and a clustering of the oxygen polyhedra of the Me atoms ensues. X-ray and neutron diffraction are used to extract Me-O coordination numbers of the bi- and three-valent Me atoms in polyphosphate glasses.

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The devitrification and structure of RE(PO₃)₃ (RE=La, Pr, Nd, Gd, Dy, Y) glasses are studied by infrared spectroscopy, X-ay diffraction and differential thermal analysis. The results from devitrification experiments show that RE(PO₃)₃ glasses (regardless of the size of RE³⁺) crystallize first to give monoclinic Yb(PO₃)₃ type crystals. The IR spectra of devitrified. La, Pr, and Nd samples differ, however, from those of Gd, Dy and Y in the range of symmetric POP stretching frequencies. To unravel the differences demonstrated in the IR spectra of devitrified RE(PO₃)₃ we performed preliminary Rietveld refinement on the crystal structure of the “metastable” Nd(PO₃)₃ [monoclinic, P2₁/c a=11.468(4) Å, b=20.438(7) Å, c=10.256(3) Å, β=97.11(1)⁰, Z=12] and compared it to previously reported Yb(PO₃)₃. Comparisons between the IR spectra of the series of RE(PO₃)₃ glasses and related crystals show that V_asPO₂ and d_asPOP stretching frequencies shift in the spectra of glasses which is explained with the alteration of chain conformation and subsequent decrease in POP bond angles in the glass network.

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We have investigated on a fabrication of porous bioactive ceramics with highly ordered three-dimensionally periodic structure and an evaluation of its biocompatibility in vitro. The porous materials were prepared as follows. Amorphous calcium phosphate (ACP) sol was poured into the three dimensionally opaline array of polystyrene (PS) latex (3 μm in size), and then this composite was heated at 900 C in order to remove the PS beads from the composite and calcine the ACP sol. An observation on the prepared porous sample with SEM revealed that the porous material had three-dimensional array of pore. A pore size of the porous material depends on the PS latex size forming an opaline array using as a template. Then, a biocompatibility of the porous material was examined by in vitro test using a simulated body fluid (SBF) with pH 7.4 at 37 C. An observation with SEM on the porous sample after soaking in an SBF exhibited bone-like apatite crystal growth and that the highly controlled porous material has a good biocompatibility in vitro.

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SiO₂-free calcium phosphate ceramics with easy machinability were prepared by crystallization of the glasses in the CaO-P₂O₅-TiO₂-Na₂O system. β-Ca₂P₂O_7- and β-Ca₃(PO₄)_2-containing glass-ceramic, which was prepared by sintering of a compact of 6OCaO-30P₂O_5-3TiO₂-7Na₂O (in mol%) glass powders at 850°C, was found to show good machinability, as confirmed by a drilling test using a conventional carbide tool. SEM observation of the glass-ceramic showed that β-Ca₂P₂O₇ crystals having a layered morphology are interlocking one another; plate-like crystals of several tens nanometers in thickness are piled up. The easy machinability of the glass-ceramics was suggested to result from the cleavage of β-Ca₂P₂O₇ crystals precipitated in the glass. By volume-crystallization of a 43CaO-30P₂O_5-25TiO_2-2Na₂O glass, the glass-ceramic containing β-Ca₂P₂O₇ and (Ca_o.5, Na)Ti₂(PO₄)₃ crystals was found to be prepared. The glass-ceramic also could be drilled using a conventional carbide tool. These glass-ceramics in the present work have relatively high strength of ~120 MPa in bending.

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The dependence of red-ox relation Sn²⁺/Sn⁴⁺ on the synthesis conditions and alloying additions was studied in the glasses of the ZnO?SnO?P²O⁵ system. The investigation of the Red-Ox stability of tin oxide in the synthesized glass was carried out in the conditions of heat treatment in different gaseous atmosphere. The ratio Sn²⁺/Sn⁴⁺ was determined by the methods of chemical analyses and Mossbauer spectroscopy. WO₃, MoO₃, B₂O₃, Sb₂O₅ were used as alloying additions. Their quantities changed from 0.1 to 3 mol.% The different influence of additions on the Sn²⁺/Sn⁴⁺ ration was shown. The composition dependence of both glass transition and crystallization temperatures have been studied by DSC.

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Mixed potassium-lead borophosphate glasses were studied in two compositional series xK₂O-(50-x)Pb0-10B₂O₃-40P₂O₅ and xK₂O-(50-x)PbO-20B₂O₃-30P₂O₅ with x = 0, 10, 20, 30, 40 and 50 mol% K₂O. The replacement of lead by potassium results in remarkable changes of the ¹¹B and ³¹P MAS NMR, Raman and infrared spectra of these glasses. The observed changes in the spectra and properties of the glasses can be ascribed mainly to the differences in the space occupied by cations, the differences in electronegativity and the field strength of the corresponding cations.

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The thermal reactions of SO₂ with natural and synthetic apatites (Aps) with different substitutions have been studied by thermogravimetric analysis. The experiments under dynamic and isothermal conditions (at temperatures ranging from 550 to 900°C) have been performed in the air-SO₂ flow with different SO₂ content (0.07%, 1%, 10%). The reactions proceed at temperatures from 400°C to 800-850°C according to the two or three-dimensional diffusion models and the reaction rate depends on temperature, SO₂ concentration and substitutions in the Aps structure (PO₄?CO₃, F?OH).

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50CuO_x-5OP₂O₅ and 40CuO_x-60P₂O₅ (molar %) glasses with different copper valence states (0<(Cu⁺)/(Cu⁺ +Cu²⁺)<0.91 were synthesized by adding glucose during glass melting. The Cu⁺ and Cu_Total contents were determined by chemical analysis. The [Cu⁺]/([Cu]⁺[Cu²⁺]) ratios of 40CuO_x-60P₂O₅ glasses are higher than those 50CuO_x- 50P₂O₅ glasses because the ultraphosphate being more acidic than metaphosphate, the formation of reduced specie is favoured. The glasses are homogeneous until 8 wt % of glucose, above of this value, the glasses crystallize.

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Zn-doped gallophosphate molecular sieve with good crystallinity was hydrothermally prepared at 170 °C, and the addition of a small amount of ZnO to the starting gel was found to promote the crystallization process and crystal growth. The characterization by chemical analysis, X-ray diffraction and molecular dynamic simulation suggested the substitution of Zn atoms for Ga atoms in the framework of Zn-doped gallophosphate molecular sieve.

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Vitreous and relevant crystalline polymorphs of P₂O₅ have been synthesised and characterised by X-ray diffraction and Raman scattering spectroscopy. On the basis of the crystallographic data of single crystals of the three varieties H?P₂O₅, O-₂O₅ and O'-P₂O₅, the interpretation of vitreous P₂O₅ Raman spectrum was given taking into consideration the short and intermediate range order. It inferred that the intermediate range order in v-P₂O₅ can mainly be described in terms of a mixture of both high temperature modifications, with however predominance of O'-P₂O₅. This hypothesis has been substantiated by in situ Raman study of v-P₂O₅ recrystallisation.

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Synthesis of nanocrystalline hydroxyapatite (HAp) by coprecipitation is presented. It is shown that the addition of PolyAcrylicAcid (PAA) acts as a crystal-growth inhibitor. In this way, needle-like nanoapatite crystals with a length of less than 100 nm are obtained. The obtained nanoparticles do not agglomerate in solution, which is believed to be due to the bonding of PAA to the surface of the apatite nanocrystals. The nanoparticles are stable into solution and they can be tailored for different applications such as coatings, composites, densified apatite and cements by controlling the size and the reactivity of the particles.

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Borophosphate glasses of the PbO-B₂O₃-P₂O₅ system were studied in two compositional series with 50 and 55 mol% PbO. The effect of compositional changes on physical properties of the glasses was investigated. Thermal stability of the glasses was evaluated by a criterion of Hruby using parameters obtained from DTA measurements. Chemical stability corresponds well with the thermal stability. Correlations were made between changes in the physical properties of the glasses and changes in their structure.

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Ultraphosphate glasses in the system CoO-P₂O₅ were prepared from 0 to 18 mol% CoO (synthesis) starting from powdery P₄O₁₀ (p. a. Merck) and fresh prepared Co₂P₄O₁₂ in closed SiO₂ glass ampoules between 900° and 950°C for about 2 hours. Higher contents above 5 mol% CoO could not be investigated by optical spectroscopy because of their very high extinction. After cooling with about 10 K min^-1, the ampoules were stored under paraffin oil in a desiccator and handled with exclusion of “water”. Measurements of density, chemical composition, optical and infrared spectroscopy followed. The optical spectra only show Co²⁺ in 6 fold coordination. Co³⁺ was not found. The structure evolution seems to follow a binary distribution model which is non-linear: the (P₂O₅)_x specific substructure units decrease, where the CoP₄O₁₁ specific substructure units increase while the CoO content increases.

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Cyclo-tri- and tetra- μ-imido-tetraphosphate has been prepared by adding aqueous sodium acetate into a cyclo-tri- and tetraphosphazenes solution. When the sodium cyclo-tri- and tetra- μ-imido-tri- and tetraphosphate was dissolved in a acidic solution, substitution from imino group to bridging oxygen and white precipitate of imido phosphoric acid were observed. When the imidophosphates were heated, decomposition to produce many kinds of condensed phosphates with or without NH and NH₂ groups at a higher temperature were occured.

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Investigations of the phase relations in the quaternary system FeO-Fe₂O₃-P₂O₅-H₂O under hydrothermal. conditions at 386° and 586°C and pressures of 0.3 GPa showed the existence of a solid solution between Fe₂(PO₄)O and Fe₄(PO₄)₃(OH)₃. The range of this solid solution extends between 0.18≤x≤0.60 according to a stoechiometry of Fe³⁺_4-xFe²⁺_3x(PO₄)₃(OH)_3-3xO_3x. The members of this series are isotypic to tetragonal β-Fe₂(PO₄)O (Spgr. I4₁/amd) and are therefore structurally related to the lazulite-type mineral phases. Rietveld analysis and ⁵⁷Fe-Mössbauer spectra showed that the structure of these phases is characterised by an disordered distribution of Fe²⁺, Fe³⁺ and vacancies on the octahedrally coordinated Me-(8f)-sites giving rise to mixed valent Fe^2.5+, Fe^2.33+ and/or Fe^2.66+ in finite clusters.

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The structure and some properties of the glasses in the ternary systems (I) BaO. B₂O₃-xP₂O₅ (x=0...60mol.%) and (II)BaO. 2P₂O₅(3P₂O₅)- xSiO₂ (x=0...40mol.%) as well as in SiO₂-P₂O₅ with molar ratio SiO₂/P₂O₅=1 were studied. The structure of glasses were characterised by their Raman spectra and compared with the phases developing in the treatment process. The chemical durability and density also was used to characterise the changes in the structure of glasses. It is shown that glasses are formed by the same structural groupings which are developed in thermal treatment of starting compositions. The changes in the glass structure causes the first 5-10 mol.% addition of other glass formers P₂O₅ or SiO₂. For these glasses in system I in concentration range of P₂O₅ 25-33.3 mol.% there are being formed the weakly connected BPO₄, BO₃ and BO₄ groups. It is shown that the most promising application by the modification of these glasses of Al₂O₃ are heat resistant coatings for Nb+1%Zr alloys.

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LnHPO₄(NO₃)·3H₂O (Ln=Er-Lu) have been synthesized by reactions of corresponding Ln₂O₃with H₃PO₄ in presence of HNO₃. The compounds have been identified by chemical analysis, thin-layer chromatography, and IR spectroscopy. It was found by XRD studies of powder samples that the obtained compounds are isotypical having orthorhombic unit cell dimensions (Z=4): ErHPO₄(NO₃)·3H₂O (a=10.157 (2), b=11.913 (2), c=6.858 (3) Å), TmHPO₄(NO₃)·3H₂O (a=10.154 (2), b=11.882 (2), c=6.830 (2) Å), YbHPO₄(NO₃)·3H₂O (a=10.149 (2), b=11.843 (2), c=6.794 (1) Å), and LuHPO₄(NO₃)·3H₂O(a=10.146 (2),b=11.827 (2), c=6.786 (2) Å). Thermal decomposition of these compounds has been investigated in the 20-1000°C range.

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Reactions of MO₂·nH₂O (M=Si, Ge, Sn, Ti, Zr, or Hf) with NH₄PO₃ have been studied in the 200-400°C range. Conditions of formation for tetraphosphates M(NH₄)₂P₄O₁₃ (M=Si, Ge, Sn, or Ti) have been elaborated. XRD studies have been performed for powder Ti(NH₄)₂P₄O₁₃ [triclinic, space group P1, with a=15.03 (1), b=7.933 (1), c=5.079 (2) Å; α=99.15 (3), β=97.05 (3), γ=83.41 (3)°] and Sn(NH₄)₂P₄O₁₃ [triclinic, space group P1, with a=15.15(1), b=8.010 (4), c=5.107 (7) Å; α=99.90 (2), β=96.82 (3), γ=83.87 (7)°]. Thermal behaviour of the tetraphosphates has been investigated in the 20-1000°C range.

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Using the thin-layer technique, phase equilibria in the open V₂O₃-P₂O₅-H₂O system have been studied within the temperature range of 25-300°C at the molar ratio P₂O₅ : V₂O₃ = (3-10) : 1. The diagram of the crystallization fields for stable phases of vanadium(III) phosphates has been constructed. The following phosphates were synthesized and identified by chemical analysis, X-ray powder diffraction, and thin-layer chromatography: monophosphates V₃H₁₅(PO₄)₈ 5H₂O and V(H₂PO₄)₃ (form A ), triphosphates VH₂P₃O₁₀ (forms I, II, III, and IV) and VH₂P₃O₁₀.2H₂O (forms I, III, and IV), cyclotetraphosphate V₄(P₄O₁₂)₃ (form A), polyphosphate V(PO₃)₃ (form C). XRD data for powder samples of novel vanadium(III) phosphates are given.

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The broad absorption band of water in phosphate glass near 3000 cm^-1contains several components belonging to different bonds of water ions. To determine the relation of these components, IR. absorption spectra in a broadened interval (up to 1400 cm^-1) and Raman scattering spectra of the same samples were measured. All the measurements were collated with quantitative determinations of water content in the studied glasses that was done by means of nuclear microanalysis methods. A pilot decomposition of Raman band of water in vitreous LiPO₃ was done using the same procedure as for the IR spectra. The calculated components show that the positions of the hydrogen-containing groups are similar in the Raman and the IR. spectra, however, their intensities being in inverse dependence. Furthermore, the Raman scattering bands are clearly different in the meta- and poly-phosphate regions. Of great importance is also the kind of the metal cation in the phosphate.

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TiO₂-?hydroxyapatite composites are noticed for its possibility of environmental applications, because HA adsorbs organic matters, and TiO₂ can decompose organic matters efficiently under irradiation. However, it has been unsolved whether bonding between TiO₂ and HA is good enough for practical use. This study reported a new knowledge on bonding between TiO₂ and HA by demonstrating selective deposition of TiO₂ on the a-face of the HA single crystal in hydrothermal condition.

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We analysed thermal (20°-1000°C) phase changes of the substrates of Zn₃(PO₄)₃.2H₂O (1) and Mg₃(PO₄)₂.8H₂0 (7) and their binary mixtures (percentage ratio 10%-90%). Thermal differential analysis (TG, DTG, DTA), IR and XR, showed that the above mentioned substances, heated for 1 hour up to 500° and 1000°C changed the structure. Samples contain: 90%, 70%, 50% Zn₃(PO₄)₃-2H₂O (1) in the binary mixtures with Mg₃(PO₄)₂.8H₂O (7) change the structure at 500°C into Zn₃(PO₄)₂ and at 1000°C in (ZnMg)₃(PO₄)₂, other binary mixture (30%, 10%) have structure Mg₃(PO₄)₂ (at 1000°C).

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Resorbable scaffolds for bone tissue engineering were fabricated from open-pore phosphate glasses coated with a thin, degradable polymer coating. This coating, consisting in a three-dimensional polymer network, was prepared by radical polymerization of a novel oligolactide macromer. It was demonstrated that the inter-connective pore structure of the phosphate glasses is preserved in the coated samples. The mechanical stability, especially the compression strength, of the scaffolds and their processibility could be significantly improved by the developed polymer coating.

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The hydrolysis of chain oligophosphates is an acid catalyzed reaction and that of ring oligophosphates is an acid and base catalyzed reaction. According to the hydrolytic property of oligophosphates, the selective ring opening of ring oligophosphate to chain oligophosphate with the same chain length as that of the ring oligophosphate can be expected. The preparation of short-chain condensed phosphate of octaphosphate was achieved by hydrolyzing cyclo-octaphosphate in a strongly basic solution.

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We propose a new route to obtain polyphosphate glasses based on sil-ver.by use a soft chemistry route, the coacervation.We precise the obtaining conditions of the silver coacervates.
By curing, we obtain glasses. It is possible to induce in these glasses silver par-ticles by the action of a wet atmosphere. These results may present some inter-ests for industrial applications.

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Porous ceramics materials as carrier of microorganism, used in the purification of water, was prepared from waste materials such as waste glass, porcelain, earthen ware, volcanic ash and oyster shell. Effective microorganisms were immobilized in ceramic carriers and then artificial waste water was supplied to conduct water purification test. The highest purification performance was achieved by using porous ceramics whose surface potential was strongly negative, which were effective for adhesion of microorganisms onto the ceramics. Much amount of microorganisms immobilized onto ceramic carrier having pores over dozens μm was observed, as microorganisms are several μm in size. All the ceramic carriers were covered by microorganisms after treatment for 10 days. The phosphorus content in water could be reduced by using calcium based ceramics.

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The sinterability of β-TCP powders doped with alkali metal or alkali earth metal ions by hot-pressing and the effect of the metal ions on the mechanical properties of hot-pressed β-TCP were investigated. Hot-pressed β-TCP doped with various amount of metal ions achieved a relative density of more than 96.7%. Undoped β-TCP showed a bending strength of about 110 MPa. Bending strength of β-TCP doped with Mg²⁺ ion up to 10 mol%was more than 140 MPa, especiallyβ-TCP doped with 8 mol% of Mg²⁺ ion showed a bending strength of 160 MPa. On the other hand, bending strength of β-TCP doped with K⁺ ion gradually decreased from 135 to 85 MPa with increasing the amount of K⁺ ion. The difference in bending strength among sintered β-TCP doped with various metal ions could be explained by the change in the unit cell volume, namely the change in theoretical density, with the addition of metal ion.

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¹⁷O-enriched crystalline sodium trimetaphosphate was prepared by crystallisation of ¹⁷O-enriched sodium metaphosphate glass. ³¹P NMR spectra (MAS and Double- Quantum filtered MAS) are in good agreement with the crystal structure resolving two inequivalent phosphorus sites. ¹⁷O NMR static spectra enable to distinguish the bridging and non-bridging oxygens. Chemical shift, quadrupolar constants and asymmetry parameters are obtained by a fitting procedure. These NMR parameters for BO and NBO are in good accordance with those previously reported for sodium metaphosphate glass. The low resolution of the static spectrum does not enable to separate the crystallographic sites of oxygen and leads to an overestimated BO/NBO ratio. The POP bond angle within the P₃O₉^3- anion could be estimated and is in good accordance with the diffraction value.

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