Mechanisms of ion exchange in crystalline zirconium phosphates. XI. Variation in unit cell dimensions and sodium ion/hydrogen ion exchange behavior in highly crystalline .alpha.-zirconium phosphates

1974 ◽  
Vol 78 (12) ◽  
pp. 1150-1153 ◽  
Author(s):  
A. Clearfield ◽  
L. Kullberg ◽  
A. Oskarsson

2011 ◽  
Vol 26 (1) ◽  
pp. 78-81 ◽  
Author(s):  
I. Fahim ◽  
A. Kheïreddine ◽  
M. Tridane ◽  
S. Belaaouad

Methods of chemical preparation and XRD data are reported for a new triphosphate CuNa3P3O10 and two cyclotriphosphates SrRbP3O9·3H2O and SrRbP3O9. SrRbP3O9·3H2O was prepared by the method of ion-exchange resin, while CuNa3P3O10 and SrRbP3O9 were obtained by total dehydration of CuNa3P3O10·12H2O and SrRbP3O9·3H2O, respectively. CuNa3P3O10 crystallizes in the hexagonal system, with space group P-31c, Z=2, and the following unit-cell dimensions: a=b=7.022(1) Å, c=9.217(1) Å, M(20)=81, F(20)=117(0.003 419, 50), and V=393.24(2) Å3. SrRbP3O9·3H2O is orthorhombic, with Z=4, space group Pnma, and the following unit-cell dimensions: a=9.120(1) Å, b=8.141(1) Å, c=15.234(1) Å, M(20)=5.1, F(20)=5.8(0.0173,199), and V=1131.1(3) Å3. SrRbP3O9 is monoclinic, with space group P21/m or P21, Z=4, and the following unit-cell dimensions: a=14.958(3) Å, b=8.503(2) Å, c=7.898(2) Å, β=122.19(2)°, M(20)=9.9, F(20)=16.5(0.0189, 64), and V=850.2(8) Å3.



Author(s):  
L. W. Labaw

Crystals of a human γGl immunoglobulin have the external morphology of diamond shaped prisms. X-ray studies have shown them to be monoclinic, space group C2, with 2 molecules per unit cell. The unit cell dimensions are a = 194.1, b = 91.7, c = 51.6Å, 8 = 102°. The relatively large molecular weight of 151,000 and these unit cell dimensions made this a promising crystal to study in the EM.Crystals similar to those used in the x-ray studies were fixed at 5°C for three weeks in a solution of mother liquor containing 5 x 10-5M sodium phosphate, pH 7.0, and 0.03% glutaraldehyde. They were postfixed with 1% osmium tetroxide for 15 min. and embedded in Maraglas the usual way. Sections were cut perpendicular to the three crystallographic axes. Such a section cut with its plane perpendicular to the z direction is shown in Fig. 1.This projection of the crystal in the z direction shows periodicities in at least four different directions but these are only seen clearly by sighting obliquely along the micrograph.



Clay Minerals ◽  
1990 ◽  
Vol 25 (4) ◽  
pp. 507-518 ◽  
Author(s):  
M. H. Ebinger ◽  
D. G. Schulze

AbstractMn-substituted iron oxides were synthesized at pH 4, 6, 8, and 10 from Fe-Mn systems with Mn mole fractions (Mn/(Mn + Fe)) of 0, 0·2, 0·4, 0·6, 0·8, and 1·0, and kept at 50°C for 40 days. The Mn mole fraction in goethite was <0·07 at pH 4 but increased to ∼0.47 at pH 6. Goethite and/or hematite formed in Fe and Fe + Mn syntheses at pH 4 and pH 6 at Mn mole fractions ≤0·8, and at Mn mole fractions ≤0·2 at pH 8 and pH 10. Hausmannite and jacobsite formed at pH 8 and pH 10 at Mn mole fractions ≥0·4. In the pure Mn syntheses, manganite (γ-MnOOH) formed at pH 4 and pH 6, whereas hausmannite (Mn3O4) formed at pH 8 and pH 10. As the Mn substitution increased, the unit-cell dimensions of goethite shifted toward those of groutite, and the mean crystallite dimensions of goethite decreased.



1980 ◽  
Vol 208 (1173) ◽  
pp. 409-414

Crystals found in the lumen of the intestine of Nematodirus battus have been studied by electron microscopy. Two of the unit cell dimensions are 16 nm x 23 nm. The possibility of an immunological significance for these crystals is considered.



1999 ◽  
Vol 55 (11) ◽  
pp. 1903-1905 ◽  
Author(s):  
John N. Lisgarten ◽  
James E. Pitts ◽  
Rex A. Palmer ◽  
Colin D. Reynolds ◽  
Minh Hoa Dao-Thi ◽  
...  

Crystals of Helix pomatia agglutinin (HPA) have been grown by the hanging-drop technique using polyethylene glycol as the precipitant at 293 K. Over a period of one to two weeks the crystals grew to maximum dimensions of 0.10 × 0.05 × 0.02 mm. The crystals belong to space group P6322, with unit-cell dimensions a = b = 63.3, c = 105.2 Å and Z = 12 identical monomers of Mr = 13 kDa, aggregating into two 78 kDa hexameric protein molecules per unit cell, each with symmetry 32 (D 3). The diffraction pattern extends to 3.6 Å at 293 K.



1968 ◽  
Vol 2 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Yoshito Matsui ◽  
Yasuhiko Syono


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