Any of a series of inorganic compounds of silicon and hydrogen with covalent bonds and the general chemical formula Simath.nH(2math.n + 2). Silanes are structural analogs of saturated hydrocarbons (see saturation; alkane) but are much less stable. All burn or explode when exposed to air and react readily with halogens or hydrogen halides to form halogenated silanes and with olefins to form alkylsilanes, products used as water repellents and as starting materials for silicones.
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Any of a class of compounds in which hydrogen is combined with another element. There are three basic types of hydrides: saline, metallic, and covalent. Saline hydrides, such as sodium hydride (NaH) and calcium hydride (CaH2), are often used as portable sources of hydrogen gas (H2). Metallic hydrides, such as titanium hydride (TiH2), are alloylike materials (see alloy) with some properties of metals, such as lustre and electrical conductivity. Covalent hydrides (see covalent bond) are mostly compounds of hydrogen and nonmetallic elements; they include water, ammonia, hydrogen sulfide (H2S), and methane. A fourth group of hydrides, dimeric (polymeric) hydrides, is sometimes recognized (see borane). Dimeric hydrides give off large amounts of energy when burned and may be useful as rocket fuels.
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Any of a homologous series of inorganic compounds of boron and hydrogen or their derivatives. The ability of boranes to form three-centre bonds (one pair of electrons is shared between three atoms) and covalent bonds allows them to form complex structures called polyhedrons, which can be considered as deltahedrons (polyhedrons with triangular faces) or deltahedral fragments. Low-molecular-weight boranes are spontaneously flammable in air, although reactivity generally decreases with increasing molecular weight. Boranes are sources of high-energy fuels for rockets and jet aircraft.
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Various metal hydrides are currently being studied for use as a means of hydrogen storage in fuel cell-powered electric cars and in batteries. The group 14 hydrides are already of vast importance in storage battery technologies. They also have important uses in organic chemistry as powerful reducing agents, and many promising uses in hydrogen economy.
Aside from electride, the hydride ion is the simplest possible anion, consisting of two electrons and a proton. Hydrogen has a relatively low electron affinity, 72.77 kJ/mol, thus hydride is so basic that it is unknown in solution. This however is deceptive since the proton is so acidic it is also unknown in solution. The reactivity of the hypothetic hydride ion is dominated by its exothermic protonation to give dihydrogen:
Deprotonation of dihydrogen complexes gives metal hydrides.
Two famous examples of transition metal hydrides are HCo(CO)4 and H2Fe(CO)4, are acidic thus demonstrating that the term hydride is used very broadly. The anion [[Potassium nonahydridorhenate|[ReH9]2−]] is a rare example of a molecular [Homoleptic] metal hydride.
Interstitial hydrides show certain promise as a way for safe hydrogen storage. During last 25 years many interstitial hydrides were developed that readily absorb and discharge hydrogen at room temperature and atmospheric pressure. They are usually based on intermetallic compounds and solid-solution alloys. However, their application is still limited, as they are capable of storing only about 2 weight percent of hydrogen, which is not enough for automotive applications.
According to the convention above, the following are "hydrogen compounds" and not "hydrides":
WIPO ASSIGNS PATENT FOR "REVERSIBLE HYDRIDE THERMAL ENERGY STORAGE CELL OPTIMIZE FOR SOLAR APPLICATIONS" (AMERICAN INVENTOR)
Sep 02, 2011; GENEVA, Sept. 2 -- Publication No. WO/2011/105989 was published on Sept. 01. Title of the invention: "REVERSIBLE hydride...
US Patent Issued to Toyota Jidosha, Hiroshima University on Sept. 27 for "Activation Method for Lithium Hydride, and Hydrogen Generation Method" (Japanese Inventors)
Oct 04, 2011; ALEXANDRIA, Va., Oct. 4 -- United States Patent no. 8,026,001, issued on Sept. 27, was assigned to Toyota Jidosha K. K....