Über Erdalkalimetalloxogallate, VI Zum Problem der Mischkristallbildung zwischen CaGa2O4 und CaAl2O4 / On Alkaline Earth Metal Oxogallates, VI About Mixed Crystal Formation of CaGa2O4-CaAl2O4

1976 ◽  
Vol 31 (12) ◽  
pp. 1604-1606 ◽  
Author(s):  
Hk. Müller-Buschbaum ◽  
W. Schmachtel
Keyword(s):  
Single Crystal ◽  
Alkaline Earth ◽  
Mixed Crystal ◽  
Earth Metal ◽  
Mixed Crystals ◽  
Alkaline Earth Metal ◽  
Crystal Formation ◽  
X Ray ◽  
Mixed Crystal Formation

Mixed crystals of the formulae CaGaAlO4 (1) and CaGa0.5Al1.5O4 (2) were investigated by X-ray single crystal work. 1 shows a tetrahedral orientation like that of CaGa2O4 (monokl.), 2 another one of CaAl2O4. A discussion of the different polyhedral arrangement of the stuffed tridymite structures is given.

Roentgenographic and thermodynamic study of the existence of mixed crystals in the LaC2-YC2 system

1985 ◽  
Vol 50 (5) ◽  
pp. 1153-1160 ◽  
Author(s):  
Bohumil Hájek ◽  
Vladimír Kohout ◽  
Vratislav Flemr
Keyword(s):  
Diffraction Study ◽  
Carbothermal Reduction ◽  
Mixed Crystal ◽  
Mixed Crystals ◽  
Crystal Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Products ◽  
Mixed Crystal Formation ◽  
Gas Pressures

The reaction heats for the mixed crystal formation in the LaC2-YC2 system were obtained from the equilibrium gas pressures measured during the carboreduction. The low positive values of the reaction heats are consistent with the X-ray diffraction study of the carbothermal reduction products of the oxides, where the formation of the (La, Y)C2 dicarbide mixed crystals was only observed in the two side regions up to 25 mol.% of each of the minority components. The composition of the gaseous hydrolysis products of the (La, Y)C2 mixed crystals corresponds to the hydrolysis products of the dicarbide. No methane was detected for samples with low yttrium contents.

Alkaline earth metal ordering in CaCu9Mg2 and SrCu9Mg2

2020 ◽  
Vol 235 (4-5) ◽  
pp. 137-141
Author(s):  
Maximilian K. Reimann ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Induction Melting ◽  
X Ray Diffraction ◽  
Muffle Furnace ◽  
Coordination Polyhedra ◽  
X Ray

AbstractThe copper-rich intermetallic compounds CaCu9Mg2 and SrCu9Mg2 were synthesized by induction melting of the elements and subsequent annealing in a muffle furnace. CaCu9Mg2 and SrCu9Mg2 crystallize with the TbCu9Mg2 type structure, space group P 63/mmc, which is a ternary ordered variant of CeNi3. The polycrystalline samples were characterized through their X-ray powder patterns. The CaCu9Mg2 structure was refined from single-crystal X-ray diffraction data. a = 504.13(9), c = 1622.5(3) pm, wR2 = 0.0635, 302 F2 values and 19 variables. The two striking coordination polyhedra in the CaCu9Mg2 structure are Ca@Cu18Mg2 and Mg@Cu12Mg3Ca. These polyhedra condense to layers which are stacked in ABA′B′ sequence. The X-ray data give no hint for Ca/Mg mixing.

Modified photoreactivity due to mixed crystal formation. I. Three mixed crystals between isostructural cobaloxime complexes

2002 ◽  
Vol 58 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Champika Vithana ◽  
Hidehiro Uekusa ◽  
Akiko Sekine ◽  
Yuji Ohashi
Keyword(s):  
Crystal Structure ◽  
Mixed Crystal ◽  
Crystal Form ◽  
Crystal Structure Analysis ◽  
Mixed Crystals ◽  
Crystal Formation ◽  
Xenon Lamp ◽  
X Ray ◽  
Mixed Crystal Formation ◽  
Cyanoethyl Group

Three crystals of 2-cyanoethyl cobaloxime complexes with 3-chloropyridine, 3-bromopyridine and 3-methylpyridine as axial base ligands are isostructural to one another. Three mixed crystals were formed between the pairs: (3-bromopyridine)(2-cyanoethyl)cobaloxime–(2-cyanoethyl)(3-methylpyridine)cobaloxime(0.45/0.55);(3-chloropyridine)(2-cyanoethyl)cobaloxime–(2-cyanoethyl)(3bromopyridine)cobaloxime (0.61/0.39); (3-chloropyridine)(2-cyanoethyl)cobaloxime–(2-cyanoethyl)(3-methylpyridine)cobaloxime (0.44/0.56). The X-ray crystal structure analysis revealed that the mixed compounds are also isostructural to the component crystals. It was found from the change in IR spectra that the 2-cyanoethyl groups in the three mixed crystals isomerized to 1-cyanoethyl groups on exposure to a xenon lamp, as observed for the 2-cyanoethyl groups in the component crystals. Rate constants for the three mixed and three component crystals, measured under the same conditions, are approximately the same, as the reaction cavities for the 2-cyanoethyl groups in the six crystals have almost the same size. For the mixed crystal between 3-chloropyridine and 3-methylpyridine complexes, the isomerization proceeded with retention of the single-crystal form. The conformation and configuration of the 1-cyanoethyl group that was produced were well explained by the shape of the reaction cavity before irradiation.

Penta-, Hepta- und Oktaiodid-Anionen in Salzen mit Erdalkalimetall-Kronenether-Kationen / Penta-, Hepta-, and Octaiodide Anions in Salts with Alkaline Earth Metal Crown Ether Cations

2010 ◽  
Vol 65 (9) ◽  
pp. 1077-1083 ◽  
Author(s):  
Christine Walbaum ◽  
Ingo Pantenburg ◽  
Gerd Meyer
Keyword(s):  
Crown Ether ◽  
Single Crystal ◽  
Crystal Structures ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Iodine Molecule ◽  
X Ray Diffraction ◽  
X Ray ◽  
Secondary Bonding

Salts of alkaline earth metal cations sequestered in dibenzo-18-crown-6 (Db18c6) and benzo-15- crown-5 (B15c5), respectively, with I5−, I7− and I82− as the anions, have been synthesized and their crystal structures determined by single-crystal X-ray diffraction. [Ca(Db18c6)(H2O)3](I5)2- (Db18c6)(H2O) (1): monoclinic, P21 (no. 4), a = 1322.1(2), b = 1849.1(2), c = 1344.0(2) pm, β = 114.70(1)◦, V = 2985.2(6) × 106 pm3, Z = 2; [Sr(B15c5)2](I7)2 (2): triclinic, P1 (no. 2), a = 973.9(5), b = 1244.0(5), c = 1293.3(5) pm, α = 115.28(1), β = 90.18(1), γ = 104.57(1)◦, V = 1360.2(10) × 106 pm3, Z = 2; [Ba(Db18c6)2]I8 (3): orthorhombic, Pbcn (no. 60), a = 1452.0(2), b = 1924.6(2), c = 1912.1(2) pm, V = 5343.3(10) × 106 pm3, Z = 4. Compound 1 contains two crystallographically independent V-shaped pentaiodide anions, I5 −, which are linked to dimers by weak interionic contacts. The unusual heptaiodide anion, I7−, in 2 can be described as a V-shaped pentaiodide unit, which is connected to a slightly widened iodine molecule to give the rare Z form. Secondary bonding distances lead to almost planar ten-membered iodine rings, which are connected through common edges to form ribbons with staircase-like folding. 3 is built of sandwich-like cations and centrosymmetric octaiodide anions, I82−. An inspection for secondary contacts reveals that the iodine substructure of 3 consists of essentially isolated octaiodide units.

Tuning of the exchange interaction and the Curie temperature by mixed crystal formation of the bridging anionic ligands

2019 ◽  
Vol 55 (18) ◽  
pp. 2652-2655 ◽  
Author(s):  
Tristan Neumann ◽  
Michał Rams ◽  
Zbigniew Tomkowicz ◽  
Inke Jess ◽  
Christian Näther
Keyword(s):  
Critical Temperature ◽  
Curie Temperature ◽  
Exchange Interaction ◽  
Coordination Polymers ◽  
Mixed Crystal ◽  
Mixed Crystals ◽  
Exchange Constant ◽  
Crystal Formation ◽  
Anionic Ligands ◽  
Mixed Crystal Formation

A strategy to continuously tune the exchange constant J and the critical temperature Tc in the 1D coordination polymers [Co(NCS)x(NCSe)2−x(pyridine)2]n is reported. For such mixed crystals, prepared by annealing and from solution, an increase of J and Tc with increasing selenocyanate content is observed.

Alkaline earth metal-based metal–organic framework: hydrothermal synthesis, X-ray structure and heterogeneously catalyzed Claisen–Schmidt reaction

2014 ◽  
Vol 43 (34) ◽  
pp. 13006-13017 ◽  
Author(s):  
Debraj Saha ◽  
Tanmoy Maity ◽  
Subratanath Koner
Keyword(s):  
Hydrothermal Synthesis ◽  
Alkaline Earth ◽  
Metal Organic Framework ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Schmidt Reaction ◽  
X Ray ◽  
Chelidamic Acid ◽  
Metal Organic ◽  
Organic Framework

Two alkaline earth metal based carboxylate framework systems, [Mg(HL)(H2O)2]n (1) and [Ca(H2L)2]n (2) (H3L = chelidamic acid) have been hydrothermally synthesized and characterized. Both compound 1 and its dehydrated species heterogeneously catalyze Claisen–Schmidt reaction.

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