Published in Crystallography Reports
Crystal structures of double calcium and alkali metal phosphates described by the general formula Ca10M(PO4)7(M = Li, Na, K) have been studied by the Rietveld method. The lattice parameters are a = 10.4203(1) and c = 37.389(1) Å (for M = Li), a = 10.4391(1) and c = 37.310(1) Å (for M = Na), and a = 10.4229(1) and c = 37.279(2) Å (for M = K); sp. gr...
Published in Crystallography Reports
Specific structural features of 1-hydroxyethane-1,1-diphosphonic acid (HEDP, H4L) and its ten salts with organic and alkali-metal cations are discussed. The following problems are addressed: (1) the dependence of the P-O bond lengths on whether the oxygen atom is protonated or not and on the total charge of the HnLn− 4 anion; (2) the variants of th...
Published in Crystallography Reports
The EPR spectra of Mn2+ ions have been studied in the vicinity of the phase transition to the ferroelectric phase in lithium heptagermanate crystals. The anomalous broadening of the resonance lines observed in the vicinity of the transition temperature TC was attributed to an increase of the contribution of low-frequency (ω
Published in Crystallography Reports
The crystal structures of K[M(Dtpa)] ⋅ 3H2O (M = Zr or Hf) and NH4[Sn(Dtpa)] ⋅ H2O are studied by X-ray diffraction. The coordination number of the metal atom in all the compounds is eight. The NH4[Sn(Dtpa)] ⋅ H2O complex is isostructural to the (H5O2)[M(Dtpa)] ⋅ H2O (M = Sn or Hf) compounds studied earlier.
Published in Crystallography Reports
The linear and the circular bulk photovoltaic and photorefractive effects in a piezoelectric La3Ga5SiO14: Fe crystal have been studied. It is shown that the photorefractive effect is induced by generation of the photovoltaic voltage.
Published in Crystallography Reports
The crystal structure of strontium hilgardite, CaSr[B5O9]Cl ⋅ H2O, was established by the method of X-ray diffraction analysis (synchrotron radiation; diffractometer equipped with a position-sensitive detector; λ = 0.688 Å; 3191 reflections with F
Published in Crystallography Reports
The method is suggested for calculating the intensity and potential of a local electric field in displacive-type ferroelectrics which is based on the introduction of a transitional zone between the region of the discrete localization of ions and the homogeneously polarized medium. The method is exemplified on the calculation of the contribution of ...
Published in Crystallography Reports
The crystal structure of 2-oxo-2,3-dihydroimidazo[1,2-a]pyridine hydrochloride, C7H7ClN2O, is determined by X-ray diffraction. The structure is solved by the direct method and refined by the least-squares procedure to R = 0.0408. The alternation of bond lengths in the molecule is inconsiderable, but does not disappear completely, since no aromatiza...
Published in Crystallography Reports
The crystal structures of two forms of the enzyme dimanganese catalase from Thermus Thermophilus (native and inhibited by chloride) were studied by X-ray diffraction analysis at 1.05 and 0.98 Å resolution, respectively. The atomic models of the molecules were refined to the R factors 9.8 and 10%, respectively. The three-dimensional molecular struct...
Published in Crystallography Reports
The elastic, piezoelectric, and dielectric characteristics of α-GeO2 crystals are studied at room temperature. The measurements were performed by the resonance method on crystals grown on α-quartz seeds from solutions in the recirculating mode. In germanium dioxide crystals, the piezoelectric moduli have high values. The characteristic features of ...
