| 词条 | Cadmium hydride |
| 释义 |
| Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 431436444 | OtherNames = Cadmium(II) hydride Cadmium dihydride |Section1={{Chembox Identifiers | CASNo = 72172-64-6 | CASNo_Ref = {{cascite|changed|??}} | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} | ChemSpiderID = 29331616 | PubChem = | SMILES = [H-].[H-].[Cd+2] | InChI = 1/Cd.2H/q+2;2*-1 | InChIKey = IVRSYBKJJXDUEX-UHFFFAOYAR | StdInChI_Ref = {{stdinchicite|changed|chemspider}} | StdInChI = 1S/Cd.2H/q+2;2*-1 | StdInChIKey_Ref = {{stdinchicite|changed|chemspider}} | StdInChIKey = IVRSYBKJJXDUEX-UHFFFAOYSA-N }} |Section2={{Chembox Properties | Formula = {{Chem|CdH|2}} | MolarMass = 113.419 g mol−1 }} |Section3={{Chembox Hazards | REL = Ca[1] | PEL = [1910.1027] TWA 0.005 mg/m3 (as Cd)[1] | IDLH = Ca [9 mg/m3 (as Cd)][1] }} |Section4={{Chembox Related | OtherCompounds = Mercury(II) hydride }} }} Cadmium hydride (systematically named cadmium dihydride) is an inorganic compound with the chemical formula {{Chem|(CdH|2|)|n}} (also written as {{Chem|([CdH|2|]}}{{Chem|)|n}} or {{Chem|CdH|2}}). It is a solid, known only as a thermally unstable, insoluble white powder. NomenclatureThe systematic name cadmium dihydride, a valid IUPAC name, is constructed according to the compositional nomenclature. Cadmium dihydride is also used to refer to the related molecular compound dihydridocadmium and its oligomers. Care should be taken to avoid confusing the two compounds. Cadmium hydride is also used as a compositional IUPAC name for the compound with the chemical formula CdH. HistoryIn 1950 a research group led by Glenn D. Barbaras, synthesized cadmium hydride for the first time. This reaction sequence consisted of demethylation{{dubious|date=December 2014}} of dimethylcadmium in diethyl ether at −78 °C, to cadmium hydride.[2] Chemical propertiesSolid cadmium hydride, on the basis of its infrared spectrum, is believed to contain hydrogen-bridge bonds.[3] Other lower metal hydrides polymerize in a similar fashion. Unless cooled below {{Convert|−20|C|F}}, cadmium hydride rapidly decomposes to produce cadmium and hydrogen:[2] {{Chem|(CdH|2|)|n}} → n Cd + n {{Chem|H|2}} DihydridocadmiumDihydridocadmium is the monomeric, molecular form with the chemical formula {{Chem|CdH|2}} (also written {{Chem|[CdH|2|]}}). It is a colorless gas that does not persist undiluted. It was produced by the gas phase reaction of excited cadmium atoms with dihydrogen, H2, and the structure determined high-resolution infrared emission spectra. The molecule is linear, with a bond length of 168.3 pm.[4] Chemical PropertiesThe two-coordinate hydridocadmium group (-CdH) in hydridocadmiums such as dihydridocadmium can accept an electron-pair donating ligand into the molecule by adduction:[3] {{Chem|[CdH|2}}] + L → {{Chem|[CdH|2|L]}} Because of this acceptance of the electron-pair donating ligand (L), dihydridocadmium has Lewis-acidic character. Dihydridocadmium can accept two electron-pairs from ligands, as in the case of the tetrahydridocadmate(2−) anion ({{Chem|CdH|4|2−}}). The compound, Cs3CdH5, prepared by the reaction of caesium hydride, CsH, and cadmium metal powder at high temperature contains the CdH42− ion, along with caesium cations, Cs+, and hydride anions, H−. The tetrahedral anion is an example of an ionic complex of CdH2. The average Cd-H bond length in CdH42− is 182pm.[5] In gaseous dihydridocadmium, the molecules form groups (trimers), being connected by van der Waals forces. The dissociation enthalpy of the dimer is estimated at 8.8 kJ mol−1.[3] References1. ^1 2 {{PGCH|0087}} {{Cadmium compounds}}{{Hydrides by group}}{{DEFAULTSORT:Cadmium Hydride}}{{Inorganic-compound-stub}}2. ^1 {{Cite journal|last1=Barbaras|first1=Glenn D.|last2=Dillard|first2=Clyde|last3=Finholt|first3=A. E.|last4=Wartik|first4=Thomas|last5=Wilzbach|first5=K. E.|last6=Schlesinger|first6=Hermann I.|title=The Preparation of the Hydrides of Zinc, Cadmium, Beryllium, Magnesium and Lithium by the Use of Lithium Aluminum Hydride|journal=Journal of the American Chemical Society|date=October 1951|volume=73|issue=10|pages=4585–4590|doi=10.1021/ja01154a025|publisher=ACS Publications}} 3. ^1 2 {{Cite journal|last1=Wang|first1=Xuefeng|last2=Andrews|first2=Lester|title=Infrared Spectra of Zn and Cd Hydride Molecules and Solids|journal=The Journal of Physical Chemistry A|date=December 2004|volume=108|issue=50|pages=11006–11013|doi=10.1021/jp046414m|publisher=ACS Publications}} 4. ^{{cite journal|last1=Shayesteh|first1=Alireza|last2=Yu|first2=Shanshan|last3=Bernath|first3=Peter F.|title=Gaseous HgH2, CdH2, and ZnH2|journal=Chemistry: A European Journal|volume=11|issue=16|year=2005|pages=4709–4712|issn=0947-6539|doi=10.1002/chem.200500332}} 5. ^{{cite journal|last1=Bortz|first1=M.|last2=Gutmann|first2=M.|last3=Yvon|first3=K.|title=Synthesis and structure determination of the first ternary cadmium hydride, Cs3CdH5|journal=Journal of Alloys and Compounds|volume=285|issue=1-2|year=1999|pages=L19–L21|issn=0925-8388|doi=10.1016/S0925-8388(99)00031-6}} 2 : Cadmium compounds|Metal hydrides |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。