The f-element/crown ether complexes. 5. Structural changes in complexes of lanthanide chloride hydrates with 18-crown-6 accompanying decreases in Ln3+ ionic radii: synthesis and structures of [M(OH2)7(OHMe)][MCl(OH2)2(18-crown-6)]2Cl7.cntdot.2H2O (M = yttrium, dysprosium)

1987 ◽  
Vol 26 (15) ◽  
pp. 2360-2365 ◽  
Author(s):  
Robin D. Rogers ◽  
Lynn K. Kurihara ◽  
Eric J. Voss
Keyword(s):  
Crown Ether ◽  
Structural Changes ◽  
Ionic Radii ◽  
Lanthanide Chloride ◽  
Crown Ether Complexes

Gas-phase relative stabilities of Tl+-crown ether complexes and Rb+-crown ether complexes

2018 ◽  
Vol 24 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Magdalena Frańska ◽  
Anna Michalak
Keyword(s):  
Mass Spectrometry ◽  
Crown Ether ◽  
Tandem Mass Spectrometry ◽  
Gas Phase ◽  
Collision Induced Dissociation ◽  
Tandem Mass ◽  
Ionic Radii ◽  
Relative Stabilities ◽  
Crown Ether Complexes ◽  
Cation Radius

The gas-phase stabilities of Tl+-crown ether complexes and Rb+-crown ether complexes were studied using the electrospray ionization-collision-induced dissociation-tandem mass spectrometry. Tl+ and Rb+ have identical ionic radii, thus a comparison of the properties of the crown ether complexes with these two cations seems to be justified. The selected crown ethers were 12C4 (it has a cavity smaller than the cation radius), 18C6 (it has a cavity of size similar to the cation radius), 24C8 (it has a cavity greater than the cation radius) and their conjugates. It has been found that the crown ether complexes of stoichiometry 1:1 with Tl+ are more or equally stable in the gas phase than the crown ether complexes with Rb+. However, 2:1 complexes with Tl+ are less stable than the complexes with Rb+.

Structural changes induced by cation ordering in ferrotapiolite

2006 ◽  
Vol 70 (3) ◽  
pp. 319-328 ◽  
Author(s):  
M. Zema ◽  
S.C. Tarantino ◽  
A. Giorgiani
Keyword(s):  
Structural Changes ◽  
Rapid Determination ◽  
Linear Increase ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
Structural Modifications ◽  
Lattice Constants ◽  
Structure Factors ◽  
Polyhedral Volumes ◽  
Degree Of Order

AbstractStructural modifications as a function of the degree of order (Q) in FeTa2O6 ferrotapiolite have been characterized by means of single-crystal X-ray diffraction (SC-XRD). A total of 26 datasets covering the range of Q between 0.154 and 1 have been obtained by thermal treatments followed by quenching of natural tapiolite crystals. Ordering of Fe2+ at the A sites and of Ta5+ at the B sites causes a linear increase in the a/c lattice constants ratio, as a consequence of a linear decrease of the c dimension and only slight modifications of the a parameter. Calibration of a/c vs. Q represents a very useful tool for a rapid determination of the degree of order of tapiolite samples. Polyhedral volumes of the two octahedral sites vary linearly with Q as a consequence of the different ionic radii of the two species. Both the sites remain almost regular at all Q values but the B site shows an increasing off-centre displacement of the cation with increasing Q. Observed structure factors of supercell reflections, characterized by l ≠ 3n, increase linearly as a function of Q, thus representing a further tool for a quick evaluation of the degree of order.

Synthesis, Characterization, and Reaction of Crown Ether Complexes of Aqua(hydroxy)(aryl)iodonium Ions

2005 ◽  
Vol 44 (1) ◽  
pp. 75-78 ◽  
Author(s):  
Masahito Ochiai ◽  
Kazunori Miyamoto ◽  
Yukie Yokota ◽  
Takashi Suefuji ◽  
Motoo Shiro
Keyword(s):  
Crown Ether ◽  
Crown Ether Complexes
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