Carbohydride

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Carbohydrides (or carbide hydrides) are solid compounds in one phase composed of a metal with carbon and hydrogen in the form of carbide and hydride ions.[ citation needed ] The term carbohydride can also refer to a hydrocarbon. [1]

Contents

Structure and bonding

Many of the transition metal carbohydrides are non-stochiometric, particularly with respect to the hydrogen that can vary in proportion up to a theoretical balanced proportion. The hydrogen and carbon occupy holes in the metal crystalline lattice. The carbon takes up octahedral sites (surrounded by six metal atoms) and the hydrogen takes up tetrahedral sites in the metal lattice. The hydrogen atoms go to sites away from the carbon atoms, and away from each other, at least 2 Å apart, so there are no covalent bonds between the carbon or hydrogen atoms. Overall the lattice retains a high symmetry of the original metal. [2]

Nomenclature

A carbodeuteride (or carbo-deuteride) is a compound where the hydrogen is of the isotope deuterium. [3] [4]

Properties

Reactions

Metal carbide hydrides give off hydrogen when heated, and are in equilibrium with a partial pressure of hydrogen that depends on the temperature.

When Ca2LiC3H is heated with ammonium chloride, the gas C3H4 (methylacetylene-propadiene) is produced. [5]

Comparisons

There are also metal cluster molecules and ions that contain both carbon and hydrogen. Methylidyne complexes contain the CH group with three bonds to a metal e.g. NiCH+ or PtCH+.

Natural occurrence

Iron carbide hydrides do not appear to be stable at the conditions present in the Earth's inner core, even though carbon or hydrogen have been proposed as alloying light elements in the core. [6]

Applications

Carbohydrides are studied for their ability in hydrogen storage. [7] Carbohydrides may be made when carbides are manufactured by milling, using hydrocarbons as a carbon source. Since the carbohydride is not the desired outcome, other material like graphite is added to try to maximise carbide production. [8]

Preparation

Transition metal carbohydrides can be produced by heating a metal carbide in hydrogen, for example at 2000 °C and 3 bars. This reaction is exothermic, and just needs to be ignited at a much lower temperature. [7] The process is called self-propagating high-temperature synthesis or SHS. [9] A hydrocarbide may be formed when the metal is milled in a hydrocarbon, for example in the manufacture of titanium carbide. [8]

Rare earth carbohydrides can be prepared by heating a metal hydride with graphite in a closed metal container, with a hydrogen atmosphere. [10]

List

Nameformulaformspace groupunit cellappearancedensitystructureref
Lithium dicalcium tricarbide hydrideCa2LiC3HtetragonalP4mbma=6.8236 c=3.7518 Z=2silver2.36has C34− [5]
Titanium carbo-deuterideTiC0.48D0.60cubicFm3ma=4.30963 [7]
Titanium carbo-deuterideTiC0.48D0.60trigonalFm31a=3.08208 c=5.0405 [7]
Zirconium carbohydrideZrC0.3H [11]
Hafnium carbohydrideHf2CH2a=3.427 c=5.476 [11] [12]
thorium carbohydrideThCH2is cubic under 380°,

and above is hexagonal.

 [13] [14]
Th2CH2hexagonala=3.083 c=5.042 [12]
Th3CH4monoclinic [12]
Niobium carbohydrideNbC0.76H0.18 [15]
Barium indium allenylide hydrideBa12InC18H4cubicIm3a=11.1447InBa12 icosahedrons [16]
Y5Si3C0.5H7.33 [17]
La2C3H1.5 [18]
La2CH4a=5.642 [19]
La2CH2monoclinicC2/ma = 7.206, b = 3.932, c = 6.739, β = 94.66 ° [19]
La15(FeC6)4HhexagonalP6a=8.7764 c=10.7355 Z=1 V=720.42silver [20]
Ytterbium carbide hydrideYb2CH2hexgonala=3.575 c=5.786 [10]
Ytterbium dicarbide hydrideYb2C2Hcubica=4.974fcc [10]
Pr3Fe27.5Ti1.5CxHmonoclinicA2/m [21]
Dy2Co17C0.2H2.8P63/mmca=8.418 c=8.165 V=501.1 [22]
Dy2Ni17C0.4H2.7P63/mmca=8.3789 c=8.054 V=489.7 [22]
Gd2ICHP63/mmca = 3.8128 c = 14.844grey8.071 [23]
Gd2BrCHP63/mmcgrey [23]
Gd2ClCHP63/mmcgrey [23]
Tb2ICHP63/mmcgrey [23]
Tb2BrCHP63/mmcgrey [23]

Related Research Articles

<span class="mw-page-title-main">Carbide</span> Inorganic compound group

In chemistry, a carbide usually describes a compound composed of carbon and a metal. In metallurgy, carbiding or carburizing is the process for producing carbide coatings on a metal piece.

<span class="mw-page-title-main">Hydride</span> Molecule with a hydrogen bound to a more electropositive element or group

In chemistry, a hydride is formally the anion of hydrogen (H−), a hydrogen atom with two electrons. The term is applied loosely. At one extreme, all compounds containing covalently bound H atoms are called hydrides: water (H2O) is a hydride of oxygen, ammonia is a hydride of nitrogen, etc. For inorganic chemists, hydrides refer to compounds and ions in which hydrogen is covalently attached to a less electronegative element. In such cases, the H centre has nucleophilic character, which contrasts with the protic character of acids. The hydride anion is very rarely observed.

<span class="mw-page-title-main">Lithium aluminium hydride</span> Chemical compound

Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula Li[AlH4] or LiAlH4. It is a white solid, discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters, carboxylic acids, and amides. The solid is dangerously reactive toward water, releasing gaseous hydrogen (H2). Some related derivatives have been discussed for hydrogen storage.

<span class="mw-page-title-main">Cubic crystal system</span> Crystallographic system where the unit cell is in the shape of a cube

In crystallography, the cubiccrystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals.

<span class="mw-page-title-main">Tantalum carbide</span> Chemical compound

Tantalum carbides (TaC) form a family of binary chemical compounds of tantalum and carbon with the empirical formula TaCx, where x usually varies between 0.4 and 1. They are extremely hard, brittle, refractory ceramic materials with metallic electrical conductivity. They appear as brown-gray powders, which are usually processed by sintering.

<span class="mw-page-title-main">Zirconium hydride</span> Alloy of zirconium and hydrogen

Zirconium hydride describes an alloy made by combining zirconium and hydrogen. Hydrogen acts as a hardening agent, preventing dislocations in the zirconium atom crystal lattice from sliding past one another. Varying the amount of hydrogen and the form of its presence in the zirconium hydride controls qualities such as the hardness, ductility, and tensile strength of the resulting zirconium hydride. Zirconium hydride with increased hydrogen content can be made harder and stronger than zirconium, but such zirconium hydride is also less ductile than zirconium.

Plutonium hydride is a non-stoichiometric chemical compound with the formula PuH2+x. It is one of two characterised hydrides of plutonium, the other is PuH3. PuH2 is non-stoichiometric with a composition range of PuH2 – PuH2.7. Additionally metastable stoichiometries with an excess of hydrogen (PuH2.7 – PuH3) can be formed. PuH2 has a cubic structure. It is readily formed from the elements at 1 atmosphere at 100–200 °C: When the stoichiometry is close to PuH2 it has a silver appearance, but gets blacker as the hydrogen content increases, additionally the color change is associated with a reduction in conductivity.

<span class="mw-page-title-main">Titanium hydride</span> Chemical compound

Titanium hydride normally refers to the inorganic compound TiH2 and related nonstoichiometric materials. It is commercially available as a stable grey/black powder, which is used as an additive in the production of Alnico sintered magnets, in the sintering of powdered metals, the production of metal foam, the production of powdered titanium metal and in pyrotechnics.

<span class="mw-page-title-main">Thorium(IV) chloride</span> Chemical compound

Thorium(IV) chloride describes a family of inorganic compounds with the formula ThCl4(H2O)n. Both the anhydrous and tetrahydrate (n = 4) forms are known. They are hygroscopic, water-soluble white salts.

<span class="mw-page-title-main">Lithium borohydride</span> Chemical compound

Lithium borohydride (LiBH4) is a borohydride and known in organic synthesis as a reducing agent for esters. Although less common than the related sodium borohydride, the lithium salt offers some advantages, being a stronger reducing agent and highly soluble in ethers, whilst remaining safer to handle than lithium aluminium hydride.

<span class="mw-page-title-main">Sodium aluminium hydride</span> Chemical compound

Sodium aluminium hydride or sodium alanate is an inorganic compound with the chemical formula NaAlH4. It is a white pyrophoric solid that dissolves in tetrahydrofuran (THF), but not in diethyl ether or hydrocarbons. It has been evaluated as an agent for the reversible storage of hydrogen and it is used as a reagent for the chemical synthesis of organic compounds. Similar to lithium aluminium hydride, it is a salt consisting of separated sodium cations and tetrahedral AlH−
4 anions.

<span class="mw-page-title-main">Magnesium hydride</span> Chemical compound

Magnesium hydride is the chemical compound with the molecular formula MgH2. It contains 7.66% by weight of hydrogen and has been studied as a potential hydrogen storage medium.

<span class="mw-page-title-main">Iron hydride</span> Index of articles associated with the same name

An iron hydride is a chemical system which contains iron and hydrogen in some associated form.

Magnesium nickel hydride is the chemical compound Mg2NiH4. It contains 3.6% by weight of hydrogen and has been studied as a potential hydrogen storage medium.

Chromium hydrides are compounds of chromium and hydrogen, and possibly other elements. Intermetallic compounds with not-quite-stoichometric quantities of hydrogen exist, as well as highly reactive molecules. When present at low concentrations, hydrogen and certain other elements alloyed with chromium act as softening agents that enables the movement of dislocations that otherwise not occur in the crystal lattices of chromium atoms.

In chemistry, a hydridonitride is a chemical compound that contains hydride and nitride ions in a single phase. These inorganic compounds are distinct from inorganic amides and imides as the hydrogen does not share a bond with nitrogen, and contain a larger proportion of metals.

A chloride nitride is a mixed anion compound containing both chloride (Cl−) and nitride ions (N3−). Another name is metallochloronitrides. They are a subclass of halide nitrides or pnictide halides.

Silicide carbides or carbide silicides are compounds containing anions composed of silicide (Si4−) and carbide (C4−) or clusters therof. They can be considered as mixed anion compounds or intermetallic compounds, as silicon could be considered as a semimetal.

Samarium compounds are compounds formed by the lanthanide metal samarium (Sm). In these compounds, samarium generally exhibits the +3 oxidation state, such as SmCl3, Sm(NO3)3 and Sm(C2O4)3. Compounds with samarium in the +2 oxidation state are also known, for example SmI2.

Hafnium compounds are compounds containing the element hafnium (Hf). Due to the lanthanide contraction, the ionic radius of hafnium(IV) (0.78 ångström) is almost the same as that of zirconium(IV) (0.79 angstroms). Consequently, compounds of hafnium(IV) and zirconium(IV) have very similar chemical and physical properties. Hafnium and zirconium tend to occur together in nature and the similarity of their ionic radii makes their chemical separation rather difficult. Hafnium tends to form inorganic compounds in the oxidation state of +4. Halogens react with it to form hafnium tetrahalides. At higher temperatures, hafnium reacts with oxygen, nitrogen, carbon, boron, sulfur, and silicon. Some compounds of hafnium in lower oxidation states are known.

References

  1. ↑ Ure, Andrew (1867). Ures̓ Dictionary of Arts, Manufactures and Mines: Containing a Clear Exposition of Their Principles and Practice. Longmans, Green and Company. pp. 648–649.
  2. ↑ Rundqvist, Stig; Tellgren, Roland; Andersson, Yvonne (August 1984). "Hydrogen and deuterium in transition metal-p element compounds: Crystal chemical aspects of interstitial solid solubility and hydride phase formation". Journal of the Less Common Metals. 101: 145–168. doi:10.1016/0022-5088(84)90092-4.
  3. ↑ Makovec, M.; Ban, Z. (June 1970). "The crystal structure of thorium carbohydrides". Journal of the Less Common Metals. 21 (2): 169–180. doi:10.1016/0022-5088(70)90115-3.
  4. ↑ Renaudin, G.; Yvon, K.; Dolukhanyan, S.K.; Aghajanyan, N.N.; Shekhtman, V.Sh. (August 2003). "Crystal structures and thermal properties of titanium carbo-deuterides as prepared by combustion synthesis". Journal of Alloys and Compounds. 356–357: 120–127. doi:10.1016/S0925-8388(03)00107-5.
  5. 1 2 Lang, David A.; Zaikina, Julia V.; Lovingood, Derek D.; Gedris, Thomas E.; Latturner, Susan E. (2010-12-15). "Ca 2 LiC 3 H: A New Complex Carbide Hydride Phase Grown in Metal Flux". Journal of the American Chemical Society. 132 (49): 17523–17530. doi:10.1021/ja107436n. ISSN   0002-7863. PMID   21090715.
  6. ↑ Litasov, K. D.; Shatskiy, A. F.; Ohtani, E. (12 October 2016). "Interaction of Fe and Fe3C with hydrogen and nitrogen at 6–20 GPa: a study by in situ X-ray diffraction". Geochemistry International. 54 (10): 914–921. doi:10.1134/S0016702916100074. S2CID   100503929.
  7. 1 2 3 4 Renaudin, G.; Yvon, K.; Dolukhanyan, S.K.; Aghajanyan, N.N.; Shekhtman, V.Sh. (August 2003). "Crystal structures and thermal properties of titanium carbo-deuterides as prepared by combustion synthesis". Journal of Alloys and Compounds. 356–357: 120–127. doi:10.1016/S0925-8388(03)00107-5.
  8. 1 2 Eryomina, M.A.; Lomayeva, S.F.; Demakov, S.L.; Yurovskikh, A.S. (15 April 2019). "SPS of "Titanium Carbide/Carbohydride – Copper" Composites". KnE Engineering. 1 (1): 246. doi: 10.18502/keg.v1i1.4416 . hdl: 10995/82850 .
  9. ↑ Dolukhanyan, S.K; Aghajanyan, N.N; Hakobyan, H.G; Shekhtman, V.Sh; Ter-Galstyan, O.P (December 1999). "The structural peculiarities of the transition metals carbohydrides produced by combustion synthesis". Journal of Alloys and Compounds. 293–295: 452–457. doi:10.1016/S0925-8388(99)00335-7.
  10. 1 2 3 Haschke, John M. (April 1975). "Preparation and some properties of ytterbium carbide hydrides". Inorganic Chemistry. 14 (4): 779–783. doi:10.1021/ic50146a016. ISSN   0020-1669.
  11. 1 2 Dolukhanyan, Seda K. (2017). "Hydridonitrides and Carbohydrides of Transition Metals". Concise Encyclopedia of Self-Propagating High-Temperature Synthesis. pp. 159–160. doi:10.1016/B978-0-12-804173-4.00071-5. ISBN   9780128041734.
  12. 1 2 3 Rexer, Joachim (1962). "Ternary metal-carbon-hydrogen compounds of some transition metals". Iowa State University.
  13. ↑ Makovec, M.; Ban, Z. (June 1970). "The crystal structure of thorium carbohydrides". Journal of the Less Common Metals. 21 (2): 169–180. doi:10.1016/0022-5088(70)90115-3.
  14. ↑ Makovec, M.; Ban, Z. (December 1970). "The crystal structure of thorium carbohydrides part II. Hexagonal thorium carbohydride". Journal of the Less Common Metals. 22 (4): 383–388. doi:10.1016/0022-5088(70)90125-6.
  15. ↑ Skripov, A.V.; Wu, H.; Udovic, T.J.; Huang, Q.; Hempelmann, R.; Soloninin, A.V.; Rempel, A.A.; Gusev, A.I. (June 2009). "Hydrogen in nonstoichiometric cubic niobium carbides: Neutron vibrational spectroscopy and neutron diffraction studies". Journal of Alloys and Compounds. 478 (1–2): 68–74. doi:10.1016/j.jallcom.2008.12.012.
  16. ↑ Blankenship, Trevor V.; Dickman, Matthew J.; van de Burgt, Lambertus J.; Latturner, Susan E. (2015-02-02). "Ca 12 InC 13– x and Ba 12 InC 18 H 4 : Alkaline-Earth Indium Allenylides Synthesized in AE/Li Flux (AE = Ca, Ba)". Inorganic Chemistry. 54 (3): 914–921. doi:10.1021/ic502315m. ISSN   0020-1669. PMID   25375309.
  17. ↑ Hassen, M.A.; McColm, I.J. (December 2000). "The preparation of high hydrogen content yttrium silicide carbides with reversible storage potential". Journal of Alloys and Compounds. 313 (1–2): 95–103. doi:10.1016/S0925-8388(00)01174-9.
  18. ↑ Kienle, L.; García García, F.J.; Duppel, V.; Simon, A. (April 2006). "Direct observation of crystallographic and chemical changes during dehydrogenation of oxygen contaminated La2C3H1.5". Journal of Solid State Chemistry. 179 (4): 993–1002. Bibcode:2006JSSCh.179..993K. doi:10.1016/j.jssc.2005.12.019.
  19. 1 2 Simon, Arndt; Gulden, Thomas (November 2004). "La2C3 und seine Reaktion mit Wasserstoff". Zeitschrift für anorganische und allgemeine Chemie (in German). 630 (13–14): 2191–2198. doi:10.1002/zaac.200400226. ISSN   0044-2313.
  20. ↑ Engstrand, Tate O.; Cope, Emily M.; Vasquez, Guillermo; Haddock, Jo W.; Hertz, Mary B.; Wang, Xiaoping; Latturner, Susan E. (2020-08-17). "Flux Synthesis of a Metal Carbide Hydride Using Anthracene As a Reactant". Inorganic Chemistry. 59 (16): 11651–11657. doi:10.1021/acs.inorgchem.0c01505. ISSN   0020-1669. OSTI   1771895. PMID   32799481. S2CID   225348956.
  21. ↑ Psycharis, V; Gjoka, M; Kalogirou, O; Niarchos, D; Papaefthymiou, V; Christodoulou, Ch (July 2000). "Magnetic properties of interstitial modified Pr3(Fe,Ti)29 hydrocarbide". Journal of Alloys and Compounds. 307 (1–2): 234–239. doi:10.1016/S0925-8388(00)00741-6.
  22. 1 2 Levytskyy, Volodymyr; Babizhetskyy1, Volodymyr; Myakush1, Oksana; Kotur1, Bogdan; Koval’chuk, Ihor (2014). "Crystal structure and hydrogenation properties of the hexagonal Dy2M17 and Dy2M17Cx". Chemistry of Metals and Alloys. 7: 26–31. doi: 10.30970/cma7.0264 . Retrieved 2020-05-14.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  23. 1 2 3 4 5 Ruck, M.; Simon, A. (November 1992). "Ln2XCHy: Kondensierte Cluster mit zwei verschiedenen interstitiellen Atomen". Zeitschrift für anorganische und allgemeine Chemie (in German). 617 (11): 7–18. doi:10.1002/zaac.19926170102. ISSN   0044-2313.
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