Thorium , crystal structure

Application of this picture to the present thorium acyl system (J,) suggests that a hydrogen atom migration to the electron deficient carbenoid p orbital must occur from a conformation (J) other than that found in the crystal structure (H) (Figure 1) to yield the cis product. These relationships are illustrated in eqs.(7) and (8) ... 

Coordination compounds of diphosphazane dioxides with uranyl or thorium ions were synthesized [475], The crystal structure of [U02(N03)2L1] [L, = Ph2P(0) N(Ph)P(0)Ph2] reveal the bidentate chelating mode of binding of the diphosphazane dioxide to these metals. The chemistry of other uranium organophosphorus and related compounds is described [476-479]. Some of the actinide complexes are presented in Table 5.16. 

The potassium salt of the podand ligand tris[3-(2-pyridyl)-pyrazol-l-yl]borate O Tp) reacts with thorium tetra(nitrate) to generate the complex (P Tp)Th(N03)3. The crystal structure of the complex reveals that the metal center is 12-coordinate, binding to the six nitrogen atoms of the podand ligand, and to two of the oxygen atoms of each nitrate. The molecule has three-fold symmetry, and the nitrates are located between the bidentate arms of the podand. 

Thorium(IV) has been reacted with a pentadentate compartmental ligand for the first crystal structure reported on a complex with Th as a binucleating metal ion. The crystal structure of the complex has been solved to reveal two Mg[Th2L3]2 6H20 units in the unit cell. Each Th2L3 anion, where all the oxygen atoms are deprotonated, comprises a dinuclear unit, where the two... 

Octaethylporphyrin (H2OEP) and thorium complex to give a crystal structure similar to that seen with H2TPP and thorium. In Th(OEP)2, the coordination environment around the thorium is an ideal square antiprism. The replacement of phenyl groups with ethyl chains removes any steric hindrance that was present in Th(TPP)2. This is illustrated in Figure 35." ... 

The X-ray crystal structure of homoleptic thorium alkoxide [Th(OCH-t-Pr2)4]2 (299) is shown in Fig. 44. Each thorium atom adopts a distorted trigonal bipyramidal geometry, and the Th208 core can be viewed as two trigonal bipyramids fused along a common axial-equatorial edge. 

The influence of unoccupied 5/band states on the Fermi surface of thorium metal has been evaluated from precise calculations of the Fermi surface areas and effective masses.Comparison of the results with those obtained from experiments showed agreement when the 5/electrons were treated as itinerant. The nature of the bonding, electronic configurations and degree of localization of 5/ electrons in the actinide elements have been described in terms of a phenomenal model constructed from a knowledge of the crystal structure, the metallic radii, melting points and enthalpies of sublimation of the elements. The 5/electrons in the elements between protactinium... 

IX.l Sulphur compounds and complexes IX.1.1 Solid and gaseous thorium sulphides IX.1.1.1 Phase diagram and crystal structures... 

Thorium tetrachloride has been shown to possess two polymorphic forms. The crystal structure or the p form, stable above 678 K, has been well established to be tetragonal with space group lAfamd and lattice parameters a = 8.486 and c = 7.465 A. The low-temperature a form, which can only be obtained if extreme care is taken in cooling the sample, has been shown to be tetragonal with space group l /a with a = (6.408 + 0.001) and c = (12.924 + 0.003) A. The p form is isomorphous with the other actinide tetrachlorides [1968BRO]. As this is the form normally obtained at room temperature, the values for this polymorph are considered to be the standard thermodynamic data for ThC cr). 

Rundle, R. E., Schull, C. G., Woolan, E. O., The crystal structure of thorium and zirconium dihydrides by X-ray and neutron diffraction, Acta Crystallogr., 5, (1952), 22-26. Cited on page 123. 

Chiotti, P., High temperatme crystal structure of thorium, J. Electro-chem. Soc., 101, (1954), 567-570. Cited on page 83. 

FER] Ferro, R., The crystal structure of thorium arsenides, Acta Crystal-... 

---