Scandium chloride structure

Scandium, tetrakis(tropolone)-stereochemistry, 1,94 Scandium, tris(acetylacetone)-structure, 1. 65, 68 Scandium, tris(tropolonate)-structure, 1,68 Scandium aryloxides spectroscopy, 2, 346 Scandium chloride... 

Other Binary Compounds.—Scandium nitride and zirconium and titanium carbide do not conform with the theoretical radii. It is possible that these crystals do not consist essentially of Sc+3, N 3, Ti+4, Zr+4 and C-4 ions, especially since zirconium and titanium nitride, ZrN and TiN, also form crystals with the sodium chloride structure but possibly also the discrepancy can be attributed to deformation of the anions, which have very high mole refraction values. 

Ripert, V., Hubert-Pfalzgraf, L.G., and Vaissermann, J. (1999) Dehydration of scandium chloride hydrate synthesis and molecular structures of ScCl3(r -DME)(MeCN), ScCL (diglyme) and [Sc2 (p-OH)2(H20)io]Cl4-2H20. Po/yAerfron, 18, 1845-1851. 

Single crystal X-ray structures of CpDoCp HScCl and CpDoCp HScMe were published. Both molecules showed a similar structure. The Cl complex is one of the very few examples of a di(cyclopentadienyl)scandium chloride without bridging chlorine atoms. This terminal Sc-Cl distance is 2.4574(12) A shorter than in a scandium chloride complex with bridging chlorine atoms like [Cp"2Sc(/r-Cl)]2 with 2.58 A. The scandium metal atom is surrounded by four ligands in a distorted tetrahedral geometry. The coordinated dimethylamino group decreases the Lewis acidity... 

The relative number of cations and anions also helps determine the most stable structure type. All the structures in Figure 12.27 have equal numbers of cations and anions. These structure types can be realized only for ionic compounds in which the number of cations and anions are equal. When this is not the case, other crystal structures must result. As an example, consider NaF, Mgp2, and SCF3 ( FIGURE 12.28). Sodium fluoride has the sodium chloride structure with a coordination number of 6 for both cation and anion. Magnesium fluoride has a tetragonal crystal structure called the rutile structure. The cation coordination number is stiU 6, but the fluoride coordination number is now only 3. In the scandium fluoride structure, the cation coordination number is stiU 6 but the fluoride coordination number has dropped to 2. As the cation/anion ratio goes down, there are fewer cations to surround each anion, and so the anion coordination number must decrease. We can state this quantitatively with the relationship... 

Scandium complexes with chloride ion in aqueous solution, and there is ion-exchange evidence for anionic species, presumably ScClJ aq, in concentrated hydrochloric acid,119 while values of K = 90 and K2 - 37 for the first two association constants have been reported.1211 Solid salts of the anions ScClt-, St Cll- and ScCl2- have been isolated with alkali metal cations.121,122 It seems likely that both the first two species are octahedral and bridged-octahedral respectively, in line with Cs2NaScCl6 which has an X-ray powder pattern in accord with a face-centred cubic structure.123... 

Hwu, S.-J., Ziebarth, R. P., von Winbush, S., Ford, J. E. Corbett, J. D. (1986). Synthesis and Structure of Double-Metal-Layered Scandium, Yttrium, and Zirconium Chloride Carbides and Nitrides, M2CI2C and M2CI2N, Inorg. Chem. 25, 283-287. 

The lanthanide and actinide halides remain an exceedingly active area of research since 1980 they have been cited in well over 2500 Chemical Abstracts references, with the majority relating to the lanthanides. Lanthanide and actinide halide chemistry has also been reviewed numerous times. The binary lanthanide chlorides, bromides, and iodides were reviewed in this series (Haschke 1979). In that review, which included trihalides (RX3), tetrahalides (RX4), and reduced halides (RX , n < 3), preparative procedures, structural interrelationships, and thermodynamic properties were discussed. Hydrated halides and mixed metal halides were discussed to a lesser extent. The synthesis of scandium, yttrium and the lanthanide trihalides, RX3, where X = F, Cl, Br, and I, with emphasis on the halide hydrates, solution chemistry, and aspects related to enthalpies of solution, were reviewed by Burgess and Kijowski (1981). The binary lanthanide fluorides and mixed fluoride systems, AF — RF3 and AFj — RF3, where A represents the group 1 and group 2 cations, were reviewed in a subsequent Handbook (Greis and Haschke 1982). That review emphasized the close relationship of the structures of these compounds to that of fluorite. 

Ternary rare earth selenites are also known, although the number of studies on them is still very limited. Giesbrecht and Giolito (1967) reported the precipitation of amorphous sodium yttrium selenite NaY(SeOj)2-3H20 by mixing yttrium chloride and sodium selenite solutions. A systematic study of the formation of the sodium, potassium, and ammonium compounds was carried out by Erametsa et al. (1973). Besides the composition of the MR(Se03)2 H20 (M = Na, K, or NH4 n = 2 or 2 ) phases they recorded the X-ray powder diffraction patterns for the different structural types and studied the compounds by IR spectroscopic and thermoanalytical techniques. A detailed study on the formation of scandium... 

Thus, lanthanide (Lu and Yb) and yttrium enolates, which were prepared from the lithium enolate of acetaldehyde and the corresponding dimeric dicyclopenta-dienyl metal chlorides [Cp2MCl2]2> were studied by NMR and IR spectroscopy, and clear evidence for the O-bound tautomer was provided in all cases. This was confirmed by a crystal structure of dimeric yttrium enolate 17 with a Y2O2 core unit > [51]. The chelate complex 18 of scandium, on the other hand, has been shown by a crystal structure to be monomeric. Here again, the metal is bound to the enolate oxygen atom (Scheme 3.7) [52]. 

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