Hydrides oxide fluorides

Syrkin Dimers, hydrides, oxides, fluorides 2 2 Physical... 

In a study which is relevant to the mechanism of hydrolysis of phosphonium salts, Glaser and Streitwieser297 studied the ions H4PO- and H3PFO- and their derivatives with Li +, NH4 and HF at the 6-31G level augmented by diffuse functions. They found that the structures of the anions are those of a hydride or fluoride ion solvated by or complexed with phosphine oxide, rather than phosphoranes297. A very important point is that earlier studies with diffuse functions yielded the pentacoordinated phosphoranes which they judged297 to be computational artifacts of the small basis set. 

The diols (97) from asymmetric dil droxylation are easily converted to cyclic sii e esters (98) and thence to cyclic sulfate esters (99).This two-step process, reaction of the diol (97) with thionyl chloride followed by ruthenium tetroxide catalyzed oxidation, can be done in one pot if desired and transforms the relatively unreactive diol into an epoxide mimic, ue. the 1,2-cyclic sulfate (99), which is an excellent electrophile. A survey of reactions shows that cyclic sulfates can be opened by hydride, azide, fluoride, thiocyanide, carboxylate and nitrate ions. Benzylmagnesium chloride and thie anion of dimethyl malonate can also be used to open the cyclic sulfates. Opening by a nucleophile leads to formation of an intermediate 3-sidfate aiuon (100) which is easily hydrolyzed to a -hydroxy compound (101). Conditions for cat ytic acid hydrolysis have been developed that allow for selective removal of the sulfate ester in the presence of other acid sensitive groups such as acetals, ketals and silyl ethers. 

Color reactions Boric acid (hydroxyquinones). Dimethylaminobenzaldehyde (pyrroles). Ferric chloride (enols, phenols). Haloform test. Phenylhydrazine (Porter-Silber reaction). Sulfoacetic acid (Liebermann-Burchard test). Tetranitromethane (unsaturation). Condensation catalysts /3-Alanine. Ammonium acetate (formate). Ammonium nitrate. Benzyltrimethylammonium chloride. Boric acid. Boron trilluoride. Calcium hydride. Cesium fluoride. Glycine. Ion-exchange resins. Lead oxide. Lithium amide. Mercuric cyanide. 3-Methyl-l-ethyl-2-phosphoiene-l-oxlde. 3-Methyl-1-phenyi-3-phoipholene-1-oxide. Oxalic acid. Perchloric acid. Piperidine. Potaiaium r-butoxIde. Potassium fluoride. Potassium... 

IODINE (7553-56-2) A powerful oxidizer. Material or vapors react violently with reducing agents, combustible materials, alkali metals, acetylene, acetaldehyde, antimony, boron, bromine pentafluoride, bromine trifluoride, calcium hydride, cesium, cesium oxide, chlorine trifluoride, copper hydride, dipropylmercury, fluoride, francium, lithium, metal acetylides, metal carbides, nickel monoxide, nitryl fluoride, perchloryl perchlorate, polyacetylene, powdered metals, rubidium, phosphorus, sodium, sodium phosphinate, sulfur, sulfur trioxide, tetraamine, trioxygen difluoride. Forms heat- or shock-sensitive compounds with ammonia, silver azide, potassium, sodium, oxygen difluoride. Incompatible with aluminum-titanium alloy, barium acetylide, ethanol, formamide, halogens, mercmic oxide, mercurous chloride, oxygen, pyridine, pyrogallic acid, salicylic acid sodium hydride, sodium salicylate, sulfides, and other materials. 

Most of the molecular relativistic calculations were performed for compounds studied experimentally various halides, oxyhalides and oxides of elements 104 through 108 and of their homologs in the chemical groups. The aim of those works was to predict stability, molecular geometry, type of bonding (ionic/covalence effects) and the influence of relativistic effects on those properties. On their basis, predictions of experimental behavior were made (see Section 3). A number of hydrides and fluorides of elements 111 and 112, as well as of simple compounds of the 7p elements up to Z=118 were also considered with the aim to study scalar relativistic and spin-orbit effects for various properties. 

Besides the two examples discussed above, the DK approach was applied to various other diatomics of heavy-main group elements, like AuH, AuCl, PbO, Pb2, TIH [14,15,18,19]. The close similarity of ZORA and DK results was also confirmed for hydrides, oxides, and fluorides of the f-elements La, Lu, Ac, and Lr at the scalar relativistic level [143]. Differences in bond lengths, vibrational frequencies, and binding energies amounted to at most 0.7 pm, 6 cm" and 6 kJ/mol, respectively. Except for cases where the quality of the basis set may be questioned, calculated results for the lanthanide species agree well with available experimental data. 

Figure 1.2 NAO/NLMO p/s hybridization ratios for hydrides and fluorides of second and third period elements in their maximum oxidation state (B3LYP/def2-TZVP resuits).

With few exceptions, the metal oxides are ionic solids and react with water to form aqueous ions, the nonmetal oxides are network covalent solids that react with water to make covalent compounds, and the amphoteric oxides of the metalloids form oligomeric polar-covalent solids. Similar relationships hold for the hydrides and fluorides of each element, with the metal forming an ionic solid and the non-metal forming a network covalent solid, although the actual demarcation line varies somewhat depending on the anion. 

The cations formed as shown by the half-reactions above are simply given the names of the metals that produced them, such as sodium for Na+ and calcium for Ca +. Since they consist of only one element, the name for each anion has an -ide ending, that is, hP", nitride CP , oxide S , sulfide H , hydride F, fluoride and Cl , chloride. An advantage in the nomenclature of ionic compounds is that it is not usually necessary to use prefixes to specify the numbers of each kind of ion in a formula unit. This is because the charges on the ions determine the relative numbers of each, as shown by the examples in Table 4.3. 

In Table 5.4 there are listed interatomic distances in MX solids of the structure type NaCl (Bl), where atoms have octahedral coordination. These compounds contain metal atoms with low ENs, forming bonds of an essentially ionic character. Therefore compounds with the B1 structure are usually considered as typically ionic. Comparison of interatomic distances in structures of the B3 and Bl types (Tables 5.3 and 5.4) shows that such increase in coordination of atoms is accompanied by an increase of the bond lengths by a factor of 1.080(9). Interatomic distances in crystal of this type are additive. Differences of the bond lengths in halides MX are Afi Na-Li = (f(Na—X) — (f(Li—X) = 0.28 A, Ai K-Na = 0.34 A, Ai Rb-K = 0.015 A, Afi Cs-Rb = 0.18 A, A /cs-NH4 = 0-17 A, A /NH4 Ag = 0.52 A, A fxi-Ag = 0.41 A. This principle works very well because of similar character of chemical bonds (for example, for halides K, Rb and Cs the deviation is ca. 5 %). On the contrary, if we compare hydrides and fluorides of alkali metals where the bond character is different, we get Ad = /(M-H)- /(M-F) = 0.15 A 35 %. In the case of oxides and chalco-genides of the MX type, the additive principle is correct within 8 %. Comparison of data in Tables 3.2, S3.1 and 5.4 shows, that the ratio of the bond lengths for = 1 to... 

In summary there has been considerable progress in our understanding of the spectroscopy of diatomic lanthanide oxides, fluorides and hydrides. Due to the ionic nature of these compounds, ligand-field models and more recently ab initio effective core potentials have made significant impact in the interpretation of the observed... 

Note that the reaction products with entries in Table 19.1 are much abbreviated compared with the analogous tables of earlier groups. Only xenon and krypton react with fluorine to produce fluorides. Therefore, instead of following the usual format of describing the hydrides, oxides, hydroxides, and halides of these elements (most of which do not exist), we adopt a historical description of the synthesis of xenon compounds and then briefly expand the discussion to include the small number of examples drawn from krypton and radon chemistry. 

Mendeleef based his original table on the valencies of the elements. Listed in Tables 1.6 and 1.7 are the highest valency fluorides, oxides and hydrides formed by the typical elements in Periods 3 and 4. 

From the tables it is clear that elements in Groups I-IV can display a valency equal to the group number. In Groups V-VII. however, a group valency equal to the group number (x) can be shown in the oxides and fluorides (except chlorine) but a lower valency (8 — x) is displayed in the hydrides. This lower valency (8 — x) is also found in compounds of the head elements of Groups V-VII. 

Similarly if tlris electrolyte is made into a composite with SrS, SrC2 or SrH2, the system may be used to measure sulphur, carbon and hydrogen potentials respectively, tire latter two over a resuicted temperamre range where the carbide or hydride are stable. The advantage of tlrese systems over the oxide electrolytes is that the conductivity of the fluoride, which conducts by F ion migration, is considerably higher. 

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