Evans Michael J, Holland Gregory P, Garcia-Garcia Francisco J, Häussermann Ulrich
Department of Chemistry and Biochemistry, Arizona State University, P.O. Box 871604, Tempe, Arizona 85287-1604, USA.
J Am Chem Soc. 2008 Sep 10;130(36):12139-47. doi: 10.1021/ja803664y. Epub 2008 Aug 13.
The quaternary hydrides (deuterides) SrGaGeH(D), BaGaSiH(D), BaGaGeH(D), and BaGaSnH(D) were obtained by investigating the hydrogenation behavior of AeGaE intermetallic compounds (Ae = Ca, Sr, Ba; E = Si, Ge, Sn), and structurally characterized by powder X-ray and neutron diffraction as well as solid state (1)H NMR investigations. The new main group metal/semimetal hydrides were found to crystallize with the simple trigonal SrAlSiH structure type (space group P3m1, Z = 1, a = 4.22-4.56 A, c = 4.97-5.30 A) and feature a two-dimensional polyanion GaEH that corresponds to a corrugated hexagon layer built from three-bonded Ga and E atoms. H is terminally attached to Ga. In BaGaSiD, a considerable degree of stacking disorder could be detected. Polyanions GaEH are electron precise, and the hydrides AeGaEH display small band gaps in the range of 0.1-0.6 eV at the Fermi level. This is in contrast to the metallic precursor phases AeGaE, which are representatives of the AlB2 structure type or variants of it. Hydrogenation has only minor consequences for the metal/semimetal atom arrangement, and the induced metal-nonmetal transition is reversible for SrGaGe, BaGaSi, and BaGaGe. BaGaSnH partially decomposes into a mixture of intermetallic compounds upon hydrogen release. Desorption temperatures are above 400 degrees C.
通过研究碱土金属镓族金属间化合物（碱土金属 = 钙、锶、钡；族金属 = 硅、锗、锡）的氢化行为，获得了四元氢化物（氘化物）SrGaGeH(D)、BaGaSiH(D)、BaGaGeH(D)和BaGaSnH(D)，并通过粉末X射线和中子衍射以及固态(1)H NMR研究对其结构进行了表征。发现新型主族金属/半金属氢化物以简单的三方SrAlSiH结构类型结晶（空间群P3m1，Z = 1，a = 4.22 - 4.56 Å，c = 4.97 - 5.30 Å），其特征是二维聚阴离子GaEH，它对应于由三键连接的镓和族金属原子构成的波纹六边形层。氢以末端方式连接到镓上。在BaGaSiD中，可以检测到相当程度的堆积无序。聚阴离子GaEH是电子精确的，并且氢化物AeGaEH在费米能级处的带隙范围为0.1 - 0.6 eV。这与金属前驱体相AeGaE形成对比，后者是AlB2结构类型或其变体的代表。氢化对金属/半金属原子排列的影响较小，并且对于SrGaGe、BaGaSi和BaGaGe，诱导的金属 - 非金属转变是可逆的。BaGaSnH在氢释放时部分分解为金属间化合物的混合物。解吸温度高于400℃。
