Zirconium crystal structure

Yu.E. Gorbunova Investigation of crystal structure of some carbonate containing hydroxocompounds of zirconium and oxyfluoroniobates -Abstract of dissertation, Moscow 1974 (in Russian). 

Although the phase which appears to be very stable for plutonium has not been observed in other An02 S03 H20 systems, phases of identical composition have been observed for Zr, Hf and Ce. The crystal structure of the zirconium compound Zr2(0H)2-(SOO 3 (H20) i,, is well known 05). One very interesting feature of the M02 S03 H20 systems for Zr, Hf and Co is that there are a large number of phases which have been observed. Some of these correspond to phases which are known for Th, U and Np. For zirconium, a series of basic sulfates is known to include Zr2(0H)2-(SOi,) 3 (H20)i, and two modifications of Zr(0H)2S0i, as the major constituents (5). Other basic sulfates such as Zr(OH)2S0if,H20,... 

Structural Studies. X-ray powder diffraction patterns for I indicate that the crystal structure is isomorphous to Zr2(0H)2-(SOO3 (H20)>. Figure 1 depicts the structure of the zirconium compound (5). The structure of I is identical to that of the zirconium analog except for variations in bond distances and angles which do not affect the overall structure. We have as yet been unable to obtain single crystals of I which are suitable for X-ray diffraction studies. 

The crystal structures of Hf 2 (OH) 2 (S0O 3 (H2O) i, (14) and Ce2(0H)2(S0i,)3 (H20)it (14) also have been determined and found to be isomorphous to the zirconium compound. The cell constants for this series of four isomorphous compounds reflect the effect of the ionic radii on the dimensions of the unit cell. The values for these cell constants are in Table II. Thus, the cell constants for the zirconium and hafnium compounds are nearly identical and smaller than the cell constants for the cerium and plutonium compounds which are also nearly identical. This trend is exactly that followed by the ionic radii of these elements. 

Figure 1. The crystal structure of Zr2(0H)2(SO4)3(H2O)4> reprinted with permission from Ref. 5, copyright 1966, American Chemical Society. Zirconium atoms are shown as solid circles, oxygen atoms as open circles. The Pu compound is isomorphous, Zr being replaced by Pu. la shows the manner in which the bridging sulfates link Pu atoms to form layers, lb shows the manner in which layers are linked through the double hydroxide bridges.

Zirconium compound, hydrothermal hydrolysis and crystal structure. .. 52-57... 

The crystal structure of a mono(cyclopentadienyl)zirconium complex containing a novel Me2Si-linked bis(amidinate) ligand was reported (Scheme 203). In this compound the central Zr atom is octahedrally coordinated with the bis(amidi-nate) acting as a tridentate ligand. ... 

The tendency to form ate complexes observed for yttrium is also seen in the preparation of a novel zirconium alkynyl complex. Reaction of Zr(Por)Cl2 (Por = OEP or TPP) with either two or three equivalents of LiC=CR (R = Ph or SiMe ) gives the trisalkynyl complexes Zr(Por)(C=CR)3Li(TFIF). An X-ray crystal structure of Zr(OEP)(C=CPh)2Li(THF) shows that all three alkynyl ligands are on... 

With boron and an appropriate amount of some sort of alkaline metal halide present in the starting materials for the solid-state reactions, then we obtain zirconium cluster materials belonging to the 6-14 family. Single-crystal X-ray data of products from iodine-rich reactions were used to determine the crystal structures of Na[(Zr6B)Cl3.87(5)lio.i3], and Cs[(Zr6B)Cl2.i6(5)lii.84] [21]. Both phases... 

Similar to the mixed-halide (Cl, I) 6-13 system, where more chlorine-rich reactions produced a new structure type, materials with an unprecedented zirconium cluster structure are obtained in the Na-Zr-(C1/I)-B system (also with. other cations, see below), when larger Cl/I ratios are used than above. Compounds characterized are Na[(Zr6B)(Cl,I)i4] and Ao.5[(Zr6B)(Cl,I)i4] (with A = Ca, Sr, Ba) [25, 26]. Single crystals of the cubic Na[(Zr6B)Clio.94(i)l3.o6] and... 

Figure 7.4. Crystal structure of the 1,1-bimetallic complex of boron and zirconium 22. Adapted by the authors.

Vinylboronates are generally less reactive than vinylzirconocenes towards various electrophiles and hence selective reactions of the latter should be possible. It was found that selective cleavage of the carbon—zirconium bond in 45 by N-halosuccinimides provides (a-haloalkenyl)boronic esters 53 in excellent chemical yields and with complete re-gioselectivity (Scheme 7.17) [54], An X-ray crystal structure determination of 45 confirmed the configuration of the four-coordinate Zr complex, with two cyclopentadienyl rings, Cl, and C(sp2) as the four ligands (Fig. 7.5) [54,126]. 

Sulphur, Selenium, and Tellurium Compounds.—The crystal structure of the metal-rich zirconium sulphide Zr Sj has been determined and each sulphur atom shown to be at the centre of a square antiprism of zirconium atoms. The reaction of ZrS2 with potassium in liquid ammonia has been shown to give four K ZrS2 phases (.x = 1, 0.86, 0.71, or 0.71—0.22) which differ in the nature of the co-ordination sites occupied by the potassium atoms between the ZrS2 layers. ZrCl reacts with NaS2P(OEt)2 in toluene to form [Zr S2P-(OEt)2 4], which appears to involve a trigonal-dodecahedral arrangement of sulphur atoms about the metal. ... 

The X-ray determination of crystal structure of tetracyclopentadienyl-hafnium has established that the molecule should be represented as [(7r-Cp)2-Hf(Cp)2], and thus resembles the titanium rather than the zirconium analogue. Both [(7i-Cp)2Hf(Cp)2] and [(it-Cp)2Zr(Cp)] exchange nonequivalent cyclopentadienyl rings very easily such that, even at — 150°C, only one sharp line is observed in the H n.m.r. spectrum. ... 

All of the steps preceding "Shape", step 10, Figure 1, are intended to make magnesium oxide and zirconia particles smaller and to mix them evenly. Figure 2 contains an illustration of what a classical "well mixed" pre-ceramic mixture might look like. Figures 3 and 4 are represenations of the crystal structures of magnesium oxide and zirconium (IV) oxide. 

Zirconium demonstrates a marked preference for the formation of bonds with oxygenated species. In aqueous solution, zirconium polymers based on hydroxyl bridged species can be found. These polymeric zirconium compounds vary in size depending on conditions such as pH, concentration, and temperature. Figure 1 illustrates the crystal structure of zirconium oxychloride, which shows it to be... 

The X-ray crystal structure of the silyl-hydrido zirconium derivative Cp2Zr(H)(SiPh3) (PMe3) showed that the silyl and phosphine ligands are in the outward position in the CpZr wedge, with the hydride ligand in between14. 

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