Beryllium forms

In addition to the oxide carboxylates, beryllium forms numerous chelating and bridged complexes with ligands such as the oxalate ion C204 , alkoxides, /9-diketonates and 1,3-diketonates. These almost invariably feature 4-coordinate Be... 

Beryllium forms a series of cyclopentadienyl complexes [Beftj -CsHiY] with Y = H, Cl, Br, Me, —C=CH and BH4, all of which show the expected C5, symmetry (Fig. 5.10a). If the pe/ifo/topfo-cyclopentadienyl group (p. 937) contributes 5 electrons to the bonding, then these are all 8-electron Be complexes consistent with the octet rule for elements of the first short... 

Notice that the beryllium atom has no unpaired electrons, the boron atom has one, and the carbon atom two. Simple valence bond theory would predict that Be, like He, should not form covalent bonds. A boron atom should form one bond, carbon two. Experience tells us that these predictions are wrong. Beryllium forms two bonds in BeF2 boron forms three bonds in BF3. Carbon ordinarily forms four bonds, not two. 

Discussion. Beryllium forms an acetylacetone complex, which is soluble in chloroform, and yields an absorption maximum at 295 nm. The excess of acetylacetone in the chloroform solution may be removed by rapid washing with O.lM-sodium hydroxide solution. It is advisable to treat the solution containing up to 10 g of Be with up to 10 mL of 2 per cent EDTA solution the latter will mask up to 1 mg of Fe, Al, Cr, Zn, Cu, Pb, Ag, Ce, and U. 

Fluorimetry is generally used if there is no colorimetric method sufficiently sensitive or selective for the substance to be determined. In inorganic analysis the most frequent applications are for the determination of metal ions as fluorescent organic complexes. Many of the complexes of oxine fluoresce strongly aluminium, zinc, magnesium, and gallium are sometimes determined at low concentrations by this method. Aluminium forms fluorescent complexes with the dyestuff eriochrome blue black RC (pontachrome blue black R), whilst beryllium forms a fluorescent complex with quinizarin. 

Beryllium forms intermetallic compounds with transition metals and phase diagrams are available Some 26 phase diagrams have also been published for Mg-transition metal systems, and intermetallic compound formation is widespread in these systems also. The extent of intermetallic compound formation decreases down group IIA, such that Ca, Sr and Ba show much less tendency for compound formation to the extent that compounds are observed only in the Ba-Pd system. 

Most chemical reactions of beryllium are similar to those of aluminum and, to a lesser extent, magnesium. In general, all the common mineral acids attack beryllium forming their corresponding salts with evolution of hydrogen ... 

Solutions of alkali metals in ammonia have been the best studied, but other metals and other solvents give similar results. The alkaline earth metals except- beryllium form similar solutions readily, but upon evaporation a solid ammoniste. M(NHJ)jr, is formed. Lanthanide elements with stable +2 oxidation states (europium, ytterbium) also form solutions. Cathodic reduction of solutions of aluminum iodide, beryllium chloride, and teUraalkybmmonium halides yields blue solutions, presumably containing AP+, 3e Be2, 2e and R4N, e respectively. Other solvents such as various amines, ethers, and hexameihytphosphoramide have been investigated and show some propensity to form this type of solution. Although none does so as readily as ammonia, stabilization of the cation by complexation results in typical blue solutions... 

Complex formation is dominated by class a or hard behaviour and is generally most favourable for the smaller ions. Beryllium forms [BeF4]2 and strong complexes with some bidentate ligands such as... 

Beryllium far surpasses its congeners in its ability to form complexes. Besides the stable BeF ion, beryllium forms many complexes having... 

Beryllium forms an enolate complex with lapachol (11a), a versatile ligand that also forms complexes with a variety of other divalent cations, e.g. Pd(ll) and ZrO(II), and trivalent metallic cations , e.g. In(lll) and Rh(lll), for which there is quantitative stability data. There are no data on related saturated derivatives, e.g. the analogous species 11b, to assess additional stabilization due to jt-metal interactions. 

Two main-group sandwich complexes deserve attention. Beryllium forms a complex with one tf-and one i -coordinated 1,2-azaborolyl ligand (Figure 11) <870M435>. It was shown that in solution the ionically bonded f/ -ring can dissociate partially. Thus, starting with a pure enantiomer, a racemate is formed after some time as both ring sites coordinate statistically in the ratio 1 1 (see Section 3.17.4). 

Beryllium forms double alkali tartrates in which beryllium not only replaces the acid hydrogen but also to some extent the hydrogen of the radical. The presence of the beryllium increases the molecular rotation not only of the tartrates but even more noticeably of the malates. 

Beryllium forms a compound with chlorine that has the empirical formula BeCl2. How would you determine whether it is an ionic compound (The compound is not soluble in water.)... 

HGA-70 Procedure. In the development of this procedure, a HGA-70 graphite furnace atomizer was used with a Perkin-Elmer 403 dual-beam spectrophotometer equipped with a deuterium background corrector. With the HGA-70 it is necessary to use grooved-type furnaces for petroleum samples to prevent the sample from running out the end of the furnace. The grooved furnaces attain a maximum temperature of 1950°C. At this temperature beryllium forms a stable carbide which prevents quantitative atomization and drastically reduces the beryllium... 

Freezing-point determinations, on both dilute and concentrated solutions, show tliat, per mol of SO any increase in basic ratio over the normal salt raises the freezing-point. The osmotic effect of the sulphate is, therefore, always decreased by dissolving in it its own hydroxide. The electrical conductivity of the basic solutions is less than that of normal solutions containing the same amount of SO,. Migration experiments show that beryllium forms no part of the anion. The basic solutions are not precipitated by crystalloids but on dialysis hydroxide is left on the membrane, and the dialyzed solution has a lower basic ratio. 

Swelling can also result from gases produced in materials, such as helium formed by (n,a) reactions and other gaseous impurities present in the metals. These traces of gas increase the concentration of voids formed upon exposure to radiation. For example, the (n,a) and (n,2n) reactions between fast neutrons and beryllium form helium and tritium gases that create swelling. 

In which of the following states would NaCl be electrically conducting (a) solid, (b) molten (that is, melted), (c) dissolved in water. Explain your answers. Beryllium forms a compound with chlorine that has the empirical formula BeC. How would you determine whether it is an ionic compound (The compound is not soluble in water.)... 

Because of its higher polarizing power, beryllium forms a range of complexes in which the beryllium atom should be treated as an electron acceptor (i.e. the vacant p orbitals are being used). Complexes such as etherates, acetylethanoates, and the tetrafluoride (BeF4 ") are formed, all of which are tetrahedral. In contrast Mg % Ca % Sr % and Ba have poor acceptor properties and form only weak complexes, even with donors such as ammonia or edta. 

Magnesium and beryllium form organic derivatives which are essentially covalent in structure and highly reactive, the M—C bonds being strongly polarized they resemble organolithium compounds in several respects. 

Of the main group metals and metalloids, only boron and possibly beryllium form compounds in which a substantial degree of (p—pV bonding is likely to occur. This property is shown particularly clearly in various boron-nitrogen compounds, but is also evident in B—O and B—X bonds. For example, the heterocyclic ring in the BN phenanthrene analogue 3.1... 

Student Annotation Bep2 is also known as beryllium c//fluoride, but because this is the only compound that beryllium forms with fluorine, the name beryllium fluoride is unambiguous. 

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