Reactions with Other Elements

On testing the shock sensitivity of materials for liquid-propellant systems, explosive reactions of graphite in OF2 were observed under shock loading at intensities corresponding to about 8200 atm [1]. 

Many common metals react with OF2, but the reaction stops after a passive metal fluoride coating is formed, see Fluor Erg.-Bd. 1, 1959, p. 230, and [2]. 

On depositing simultaneously OF2 diluted in Ar and a beam of Li, Na, K, or Mg atoms onto a salt window at 15 K, absorption bands due to the appropriate metal fluorides and weakly bonded MF --OF dimers were observed. In the case of Li the formation of LiOF is also assumed [3]. 

Mass spectrometry studies on OF2 indicate the formation of HgOF by reaction between OF2 and Hg at temperatures above 520 K [4]. 

Heating a platinum sponge in an atmosphere of OF2 leads to the formation of 02PtFe [5, 6]. The introduction of OF2 into a uranium(IV) solution induces chemiluminescence by forming the ion in an excited state [7]. 

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There is no natural curium on Earth. All of its isotopes are man-made and artificially produced through nuclear reactions with other elements. The curium isotope Cm-242 was first produced by bombarding plutonium-239 with helium nuclei (alpha particles), which contributed neutrons that changed Pu to g Cm. 

Inert Gases Explosive Compounds. Until quite recently, the noble gases (Xe, Kr, A, Ne, Ra He) were considered chemically inert and incapable of reaction with other elements. While this concept remains generally unchanged, at least a few noble gas compds can be prepd. 

The biochemical reduction of sulfate to sulfide by bacteria of the genus Desulfovibrio in anoxic waters is a significant process in terms of the chemistry of natural waters since sulfide participates in precipitation and redox reactions with other elements. Examples of these reactions are discussed later in this paper. It is appropriate now, however, to mention the enrichment of heavy isotopes of sulfur in lakes. Deevey and Nakai (13) observed a dramatic demonstration of the isotope effect in Green Lake, a meromictic lake near Syracuse, N. Y. Because the sulfur cycle in such a lake cannot be completed, depletion of 32S04, with respect to 34S04, continues without interruption, and 32S sulfide is never returned to the sulfate reservoir in the monimolimnion. Deevey and Nakai compared the lake to a reflux system. H2S-enriched 32S diffuses to the surface waters and is washed out of the lake, leaving a sulfur reservoir depleted in 32S. The result is an 34S value of +57.5% in the monimolimnion. 

First of all, note that the term "oxidation" is based on a historical premise that is not relevant from a more modem perspective namely, the combining of another element with oxygen to form a simple binary compounds i.e., an "oxide" similarly, the removal of oxygen atoms from an oxide molecule leaving the "reduced" element was the concept intended for the term "reduction". Although this idea works fairly well for many of the more simple interactions of oxygen with both metal and non-metal elements, a better, more comprehensive, definition that includes similar reactions with other elements, such as fluorine and chlorine, evolved that was based on the transfer of electrons from one atom (or ion) to another. 

A final step in manufacture is to coat the fibre with SiC or B4C this provides protection against reactions with other elements at high operating temperatures and ensures that the fibre retains its tensile strength at elevated temperature. Typically, the W wire substrate has an 8 pm diameter, the... 

Atoms having outer orbits that are not full are unstable and will undergo chemical reactions with other elements to gain full outer orbits. 

Their method of production is summarized in Fig. 28.28c in which atom X represents an arbitrary N content. Processing conditions (heat treatment in particular) determine the mechanical properties of the carbon fibres. Both pitch- and PAN-based carbon fibres (Fig. 28.29) are stronger and have a higher modulus of elasticity (Young s modulus) than those derived from rayon. They therefore have wider applications. Carbon fibres usually require a protective coating to provide resistance to reaction with other elements at elevated temperature. 

Preparative aspects of inorganic chemistry are covered by the Encyclopedia of Chemical Reactions compiled by C. A. Jacobson and C. A. Hampel (Reinhold, 1946-59) which lists known chemical reactions in eight volumes. Elements are arranged alphabetically by their chemical symbol and for each its reactions with other elements or compounds are listed, with the formula, a comment and the bibliographic reference. Each volume contains an index to reagents and to substances obtained, arranged alphabetically by formula. 

Electrons are not only charged, they also have a characteristic physicists call spin. Pairing two electrons by spin, which has two possible values, up or down, confers additional stability. Bei yllium (Be, atomic number 4) has two spin-paired electrons in its second shell that are easily given up in chemical reactions. Beryllium shares this characteristic with other elements in column two, the alkaline earth metals. These atoms also generally form ionic bonds. Boron... 

Two approaches have been used in the synthesis of these types of compounds. Small boron-phosphorus ring compounds can serve as building blocks, and addition and elimination reactions with other main group elements can then extend the cage structure (see Schemes 23 and 24, Section 12.12.6.4.5). Alternatively, an unsaturated carbenoid fragment can be added to the bicyclic fragment as illustrated in Scheme 31 <1998IC490>. 

The term hetero rearrangement is not limited to those reactions in which only the initially electron-deficient atom is something other than carbon, but may be applied to rearrangements in which any of the carbon atoms of formula L have been replaced with other elements. 

Californium is a synthetic radioactive transuranic element of the actinide series. The pure metal form is not found in nature and has not been artificially produced in particle accelerators. However, a few compounds consisting of cahfornium and nonmetals have been formed by nuclear reactions. The most important isotope of cahfornium is Cf-252, which fissions spontaneously while emitting free neutrons. This makes it of some use as a portable neutron source since there are few elements that produce neutrons all by themselves. Most transuranic elements must be placed in a nuclear reactor, must go through a series of decay processes, or must be mixed with other elements in order to give off neutrons. Cf-252 has a half-life of 2.65 years, and just one microgram (0.000001 grams) of the element produces over 170 mhhon neutrons per minute. 

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