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Hydride is the name given to the negative ion of hydrogen, H−. Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Although this ion does not exist except in extraordinary conditions, the term hydride is widely applied to describe compounds of hydrogen with other elements, particularly those of groups 1–16. A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in The variety of compounds formed by hydrogen is vast, arguably greater than that of any other element. Various metal hydrides are currently being studied for use as a means of hydrogen storage in fuel cell-powered electric cars and batteries. A fuel cell is an electrochemical conversion device It produces electricity from Fuel (on the Anode side and an oxidant (on the In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy They also have important uses in organic chemistry as powerful reducing agents, and many promising uses in hydrogen economy. Organic chemistry is a discipline within Chemistry which involves the scientific study of the structure properties composition reactions, and preparation A reducing agent (also called a reductant or reducer) is the element or a compound in a Redox (reduction-oxidation reaction (see Electrochemistry The hydrogen economy is a proposed method of deriving the Energy needed for Motive power (cars boats airplanes buildings or portable electronics by reacting

Every element of the periodic table (except some noble gases) forms one or more hydrides. The periodic table of the chemical elements is a tabular method of displaying the Chemical elements Although precursors to this table exist its invention is History Noble gas is translated from the German noun de ''Edelgas'' first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity These compounds may be classified into three main types by the predominant nature of their bonding:

Contents

Hydride ion

See also: hydrogen anion. The Hydrogen anion is a negative Hydrogen ion, H− It is an important constituent of the atmosphere of Stars, such as the Sun

Aside from electride, the hydride ion is the simplest possible anion, consisting of two electrons and a proton. An electride is an ionic compound in which an Electron is the Anion. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Hydrogen has a relatively low electron affinity, 72. The electron affinity, E ea of an Atom or Molecule is the energy required to detach an electron from a singly charged negative 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:

H− + H+ → H2; ΔH = −1676 kJ/mol

As a result, the hydride ion is one of the strongest bases known. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 In Thermodynamics and molecular chemistry, the enthalpy (denoted as H, h, or rarely as χ) is a quotient or description of In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and It would extract protons from almost any hydrogen-containing species. The low electron affinity of hydrogen and the strength of the H–H bond (436 kJ/mol) means that the hydride ion would also be a strong reducing agent:

H2 + 2e− ⇌ 2H−; Eo = −2. A reducing agent (also called a reductant or reducer) is the element or a compound in a Redox (reduction-oxidation reaction (see Electrochemistry In Electrochemistry, the standard electrode potential, abbreviated Eo E0 or EO (with a superscript Plimsoll character pronounced 25 V

Ionic hydrides

In ionic, or saline, hydrides, the hydrogen is viewed as a pseudohalide. A halide is a Binary compound, of which one part is a Halogen Atom and the other part is an element or radical that is less The saline hydrides are insoluble in conventional solvents, reflecting their nonmolecular structures. H− has stable electron configuration of helium with a filled 1s-orbital. In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical Ionic hydrides also feature an electropositive metal, usually one of the alkali metals or alkaline earth metals. Trends The alkali metals show a number of trends when moving down the group - for instance decreasing electronegativity increasing reactivity and decreasing melting and boiling Biological occurrences Beryllium's low aqueous solubility means it is rarely available to biological systems it has no known role in living organisms and when encountered These hydrides are called binary if they only involve two elements including hydrogen. Chemical formulae for binary ionic hydrides typically MH (as in LiH). A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 As the charge on the metal increases, the M-H bonding becomes more covalent as in MgH2 and AlH3. Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 WikipediaNaming Ionic hydrides are commonly encountered as basic reagents in organic synthesis:

C6H5C(O)CH3 + KH → C6H5C(O)CH2K + H2

Such reactions are heterogeneous because the KH does not dissolve. A reagent or reactant is a substance or compound consumed during a Chemical reaction. Organic synthesis is a special branch of Chemical synthesis and is concerned with the construction of Organic compounds via Organic reactions Organic Acetophenone is the Organic compound with the formula C6H5C(OCH3 Potassium hydride, KH is a Chemical compound of Potassium and Hydrogen. Typical solvents for such reactions are ethers. Ether is a class of Organic compounds which contain an ether group — an Oxygen Atom connected to two (substituted Alkyl Water cannot serve as a medium for pure ionic hydrides or LAH because the hydride ion is a stronger base than hydroxide. Water is a common Chemical substance that is essential for the survival of all known forms of Life. In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and In Chemistry, hydroxide is the most common name for the diatomic Anion OH− consisting of Oxygen and Hydrogen Hydrogen gas is liberated in a typical acid-base reaction.

NaH + H2O → H2 (gas) + NaOH ΔH = −83. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the 6 kJ/mol, ΔG = −109. In Thermodynamics, the Gibbs free energy ( IUPAC recommended name Gibbs energy or Gibbs function) is a Thermodynamic potential which 0 kJ/mol

Alkali metal hydrides react with metal halides. Lithium aluminium hydride (often abbreviated as LAH) arises from reactions with aluminium chloride. Lithium aluminium hydride ( Li[[Aluminium Al]] H4) commonly abbreviated to LAH, is a Reducing agent used in Organic synthesis Aluminium chloride (AlCl3 is a compound of Aluminium and Chlorine.

4 LiH + AlCl3 → LiAlH4 + 3 LiCl

Covalent hydrides

In covalent hydrides, hydrogen is covalently bonded to more electropositive element such as p-block (boron, aluminium, and Group 4-7) elements as well as beryllium. Lithium hydride ( Li[[Hydride H]] is the compound of Lithium and hydrogen " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. WikipediaNaming Beryllium hydride, BeH2 is a Chemical compound of Beryllium and Hydrogen. Common compounds include the hydrocarbons and ammonia could be considered as hydrides of carbon and nitrogen, respectively. In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Charge neutral covalent hydrides that are molecular are often volatile at room temperature and atmospheric pressure. Some covalent hydrides are not volatile because they are polymeric—i. e. nonmolecular—such as the binary hydrides of aluminium and beryllium. Replacing some hydrogen atoms in such compounds with larger ligands, one obtains molecular derivatives. In Chemistry, a ligand is either an Atom, Ion, or Molecule (see also Functional group) that bonds to a central metal generally For example, diisobutylaluminium hydride (DIBAL) consists of two aluminium centers bridged by hydride ligands. Diisobutylaluminium hydride, DIBAL DIBAL-H or DIBAH is a Reducing agent with the formula ( i -Bu2AlH2 where i -Bu represents Hydrides that are soluble in common solvents are widely used in organic synthesis. Organic synthesis is a special branch of Chemical synthesis and is concerned with the construction of Organic compounds via Organic reactions Organic Particularly common are sodium borohydride (NaBH4) and lithium aluminum hydride and hindered reagents such as DIBAL. Sodium borohydride, also known as sodium tetrahydroborate, has the Chemical formula Na[[boron B]] H 4

Transition metal hydrido complexes

Main article: Transition metal hydride

Most transition metal complexes form molecular compounds that contain one or more hydride ligands. Transition metal hydrides are Chemical compounds containing a Transition metal bonded to Hydrogen. The term complex in Chemistry is usually used to describe molecules or ensembles formed by the combination of Ligands and metal Ions. Usually such compounds are discussed in the context of organometallic chemistry. Organometallic chemistry is the study of Chemical compounds containing bonds between Carbon and a Metal. They are intermediates in many industrial processes that rely on metal catalysts, such as hydroformylation, hydrogenation, and hydrodesulfurization. Hydroformylation, also known as oxo synthesis, is an important industrial process for the production of aldehydes from alkenes Hydrogenation is the Chemical reaction that results in addition of Hydrogen (H2 Hydrodesulfurization (HDS is a Catalytic chemical process widely used to remove Sulfur (S from Natural gas and from refined petroleum products

Deprotonation of dihydrogen complexes gives metal hydrides. Dihydrogen complexes are Coordination complexes containing intact H2 as a Ligand.

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 [ReH9]2− is a rare example of a molecular homoleptic metal hydride. Potassium nonahydridorhenate is an Inorganic compound with the formula K2ReH9 In Inorganic chemistry, a homoleptic Chemical compound is a Metal compound with all Ligands identical

Interstitial hydrides of the transitional metals

Structurally related to the saline hydrides, the transition metals form binary hydrides which are often non-stoichiometric, with variable amounts of hydrogen atoms in the lattice, where they can migrate through it. Stoichiometry (sometimes called reaction stoichiometry to distinguish it from composition stoichiometry is the Calculation of Quantitative (measurable In materials engineering, the phenomenon of hydrogen embrittlement is a consequence of interstitial hydrides. Materials Science or Materials Engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of Science and Hydrogen embrittlement (or hydrogen grooving) is the process by which various metals most importantly high-strength Steel, become brittle and crack following exposure Palladium absorbs up to 900 times its own volume of hydrogen at room temperatures, forming palladium hydride, and was therefore once thought as a means to carry hydrogen for vehicular fuel cells. Palladium (pronounced \pəˈleɪdiəm\ is a rare and lustrous silvery-white metal that was discovered in 1803 by William Hyde Wollaston, who named it palladium after the Palladium hydride is metallic Palladium that contains a substantial quantity of Hydrogen within its Crystal lattice. A fuel cell is an electrochemical conversion device It produces electricity from Fuel (on the Anode side and an oxidant (on the Hydrogen gas is liberated proportional to the applied temperature and pressure but not to the chemical composition.

Interstitial hydrides show certain promise as a way for safe hydrogen storage. See also Hydrogen economy Hydrogen storage describes the methodologies for storing H2 for subsequent use 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. Intermetallics or intermetallic compounds is a term that is used in a number of different ways 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.

Nomenclature

The following is a list of the nomenclature for the hydride derivatives of main group compounds:

According to the convention above, the following are "hydrogen compounds" and not "hydrides":

Examples:

Isotopes of hydride

Protide, deuteride, and tritide are used to describe ions or compounds, which contain enriched hydrogen-1, deuterium or tritium, respectively. Isotope separation is the process of concentrating specific Isotopes of a Chemical element by removing other isotopes for example separating Natural uranium A hydrogen atom is an atom of the chemical element Hydrogen. The electrically neutral Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen.

Precedence convention

According to IUPAC convention, by precedence (stylized electronegativity), hydrogen falls between group 15 and group 16 elements. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general See also Gold chalcogenides Periodic table Therefore we have NH3, 'nitrogen hydride' (ammonia), versus H2O, 'hydrogen oxide' (water). Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Water is a common Chemical substance that is essential for the survival of all known forms of Life.

See also

External links

In chemistry hydron is the general name for the positive Hydrogen H+ Cation. In Chemistry, hydronium is the obsolete name for the Cation H 3 O + derived from Protonation of Water

Dictionary

hydride

-noun

  1. (chemistry) a compound of hydrogen with a more electropositive element
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