Titanium radii

The most common oxidation state of niobium is +5, although many anhydrous compounds have been made with lower oxidation states, notably +4 and +3, and Nb can be reduced in aqueous solution to Nb by zinc. The aqueous chemistry primarily involves halo- and organic acid anionic complexes. Virtually no cationic chemistry exists because of the irreversible hydrolysis of the cation in dilute solutions. Metal—metal bonding is common. Extensive polymeric anions form. Niobium resembles tantalum and titanium in its chemistry, and separation from these elements is difficult. In the soHd state, niobium has the same atomic radius as tantalum and essentially the same ionic radius as well, ie, Nb Ta = 68 pm. This is the same size as Ti ... 

Identify the element with the larger atomic radius in each of the following pairs (a) vanadium and titanium (b) silver and gold (c) vanadium and tantalum (d) rhodium and iridium. 

When the logarithm of k is plotted against metallic radius (Fig. 5) a correlation is observed for those elements with radii in the range 1.35-1.45 A. The correlation does not extend to those elements of the first transition series for which the radii are less than 1.30 A (with the exception of titanium, which obeys the correlation). This correlation lends some support to the view that there may be a critical intermediate in the exchange process the facile formation of which requires the matching of... 

EXAMPLE 2.2 Use of the Sedimentation Equation for Particle Size Determination. A titanium dioxide pigment of density 4.12 g cm 3 is suspended in water at 33°C. At this temperature, the density and viscosity of water are 0.9947 g cm-3 and 7.523 10-3 P, respectively. A particle size analyzer (SediGraph, Micromeritics Instruments Corp., Norcross, GA 30093) plots the following data for cumulative weight percent versus equivalent spherical radius ... 

The two magnetic stages are a 30-cm radius followed by an electrostatic analyzer with a radius of 43.26 cm. The vacuum system is metal and is bakeable to 300°C. The analyzer region of the instrument is pumped with ion pumps and is maintained at a pressure 10"9 torr. A combination titanium sublimation-ion pump is used to obtain operating pressures in the source region in the 10"8 torr range. A Nier thick-lens source (8), used in conjunction with a sample wheel arrangement (9), makes it possible to analyze as many as 10 samples per day. 

Titanium metal has a density of 4.54 g/cm3 and an atomic radius of 144.8 pm. In what cubic unit cell does titanium crystallize ... 

The formal potential is determined from the mean of the anodic and cathodic peak potential of the CV in Fig. 51.3. The titanium nitride samples are very smooth. Atomic force microscopy yielded a value of the roughness mean square of 0.516 nm on an area of 5 x 5 pm2. This means that the sample roughness is negligible against the radius of the UME and the working distance in the SECM experiment and the approximation of the sample surface as a simple plane is valid. 

Hightened reactivity of functional groups (e.g. Cl, Br, OH, OR, OCOR, NH2, SH) at the atoms of silicon, aluminum, titanium, phoshorus and other elements in comparison with their reactivity binded with oxygen. This is due to the fact that the silicon atom is one and a half times bigger than the carbon atom it has a covalent radius of 0.117 nm, whereas the radius of the carbon atom is only 0.077 nm. It follows that functional groups of the Si atom are much more distanced from each other than... 

The second apparent factor influencing the mobility of the atoms and hence the sequence of compound-layer formation is atomic radii of reacting elements. Clearly, the direct juxtaposition of the melting points to decide which compound has a greater chance to occur first is only justified if the atomic radii are identical or close for both elements, as is the case with titanium and aluminium, the atomic radius being 0.146 nm and 0.143 nm, respectively.152 153 Similarly, the juxtaposition, with the same purpose, of the atomic radii is valid only if the melting points of both elements are close. An example of this kind is the Al-Mg binary system already considered in Section 2.8.3 of Chapter 2. 

As the atomic radius of nickel is much less than that of titanium, not only NiAl3 but also Ni2Al3 can occur at the Ni-Al interface, especially at... 

A much lower stereospecificity of the ZrBz4—[Al(Me)0]x catalyst for styrene polymerisation (ca 58% of the hot acetone-insoluble polymer fraction [56]) compared to that for the respective Ti-based catalyst should be noted. This can be explained in terms of the larger radius of zirconium than titanium, thus resulting in the impossibility of sufficiently effective chain end stereocontrol. 

In VCK lattice P-modification of titanium of emptiness with radius 0,44 nm almost precisely correspond to nuclear radius of hydrogen 0,41 nm, and free fluctuations of atoms between knots do not occur. Hence, the system is more stable. Therefore, the hydrogen is well dissolved in P-phase (up to 2 %), stabilising it [3],... 

As it is shown in Table 1, the hydrogen has the highest speed of diffusion. The size of radius of its atom is 0,41 TO"10 m, and the size of octahedral pore in a-Ti is 0.62T0 10 m, i.e. is 34 % less than the size of octahedral pore of a crystal lattice of titanium. Moving along octahedral pores, the hydrogen freely and quickly penetrates in the depth of a particle. 

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