Zirconium dihydride

Surface zirconium hydrides 1 result from hydrogenolysis of the Zr-C bonds of A at 150°C. A monohydride zirconium supported complex is the major species formed, but some zirconium dihydrides are present along with surface silanes, [Sijj-H, the product of reduction of siloxane bridges by the very reducing zirconium hydrides [6]. These latter are catalytically inert. The surface zirconium hydrides are stable up to 200°C under vacuum or hydrogen. Complexes 1 were fiilly characterized by physical techniques (in situ IR, EXAFS) and their chemical reactivity determined (towards O2, H2O, R-X, ROH, olefins) [6]. 

ZIRCONIUM DIHYDRIDE (7740-99-6) Flammable solid dangerous when wet. A powerful reducing agent violent reaction with oxidizers. Dusts of zirconium compounds ignite and explode in a carbon dioxide atmosphere. Spontaneous ignition occurs when heated in air. 

Scheme 19 Reactivity of zirconium dihydride supported on siiica with COp and NpO.

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. 

In reaction with carbon monoxide, as well as many other Lewis acid-base type reactions, the vacant orbital is often the initial site of reaction. Thus the reaction between zirconium dihydride and carbon monoxide initially forms a carbonyl metal dihydride complex about the zirconium metal atom concluding in the formation of the ethoxide derivative after hydrogenation as shown in scheme 1 This reaction is important because it leads to the formation of a variety of compounds that have M-O bonds. But, it is also important because it signals a probable mechanistic mode for attack by a Lewis base. 

The fate of 10 depends on whether or not the zirconium dihydrido species, (T75-C5Me5)2ZrH2, is present. In the presence of the dihydride, further reduction occurs to yield the methoxide complex (7). In the absence of the dihydride, 10 undergoes a dimerization reaction, yielding 11 ... 

The diorganotin dihydrides react with catalysts based on the metallocenes of titanium, zirconium, or hafnium459 162 to give oligo- and polystannanes. 

Tetraphosphorus decasulfide, 4878 Thorium dihydride, 4489 Titanium, 4919 Titanium carbide, 0561 Titanium dihydride, 4490 Zinc stearate, 3897 Zirconium, 4928... 

Magnesium hydride, 4463 Magnesium-nickel hydride, 4464 Plutonium(III) hydride, 4509 Poly (germanium dihydride), 4415 Poly (germanium monohydride), 4413 Potassium hydride, 4427 Rubidium hydride, 4450 Sodium hydride, 4444 f Stibine, 4510 Thorium dihydride, 4489 Thorium hydride, 4540 Titanium dihydride, 4490 Titanium-zirconium hydride, 4491 Trigermane, 4421 Uranium(III) hydride, 4511 Uranium(TV) hydride, 4541... 

Reaction with hydrogen occurs at temperatures of 300 to 1,000°C forming a brittle dihydride, ZrH2. Zirconium combines with halogens at high temperatures forming tetrahalides. Reactions occur in the range 200 to 400°C. Sohd tetrahalides sublime above 300°C. 

Tetraphosphorus decasulfide, 4872 Thorium dihydride, 4483 Titanium, 4913 Titanium carbide, 0558 Titanium dihydride, 4484 Zinc stearate, 3891 Zirconium, 4922... 

Magnesium—nickel hydride, 4458 Plutonium(III) hydride, 4504 Poly(germanium dihydride), 4409 Poly(germanium monohydride), 4407 Potassium hydride, 4421 Rubidium hydride, 4444 Sodium hydride, 4438 f Stibine, 4505 Thorium dihydride, 4483 Thorium hydride, 4535 Titanium dihydride, 4484 Titanium—zirconium hydride, 4485 Trigermane, 4415 Uranium(III) hydride, 4506 Uranium(IV) hydride, 4536 Zinc hydride, 4486 Zirconium hydride , 4487 See COMPLEX HYDRIDES, PYROPHORIC MATERIALS See entry LANTHANIDE—TRANSITION METAL ALLOY HYDRIDES... 

The trinuclear structure of 40 was elucidated by X-ray crystallography. The molecule lies on a twofold axis through Zr(2), and the Zr-Zr and Zr-H distances are represented schematically in Figure 6. The three //-hydride ligands and three zirconium atoms are essentially coplanar, with //-hydrides above and below the plane. There are five hydrides and three zirconium atoms so compound 40 is formally mixed-valent Zr(m)Zr(lv)2. The shorter Zr-Zr distances in 40 compared to those seen in Zr(iv) dihydride dimers are consistent with the presence of Zr-Zr bonding.24... 

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