Polyanionic Hydrides from Polar Intermetallics AeE2 (Ae = Ca, Sr, Ba; E = Al, Ga, In)
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- 作者：Thomas Bjö ; rling ; Dag Noré ; us ; and Ulrich Hä ; ussermann
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：January 25, 2006
- 年：2006
- 卷：128
- 期：3
- 页码：817 - 824
- 全文大小：364K
- 年卷期：v.128,no.3(January 25, 2006)
- ISSN：1520-5126
文摘
The hydrogenation behavior of the polar intermetallic systems AeE2 (Ae = Ca, Sr, Ba; E = Al,Ga, In) has been investigated systematically and afforded the new hydrides SrGa2H2 and BaGa2H2. Thestructure of these hydrides was characterized by X-ray powder diffraction and neutron diffraction ofthe corresponding deuterides. Both compounds are isostructural to previously discovered SrAl2H2 (spacegroup P
m1, Z = 1, SrGa2H2/D2: a = 4.4010(4)/4.3932(8) Å, c = 4.7109(4)/4.699(1) Å; BaGa2H2/D2: a =4.5334(6)/4.5286(5) Å, c = 4.9069(9)/4.8991(9) Å). The three hydrides SrAl2H2, SrGa2H2, and BaGa2H2decompose at around 300 
C at atmospheric pressure. First-principles electronic structure calculationsreveal that H is unambiguously part of a two-dimensional polyanion [E2H2]2- in which each E atom istetrahedrally coordinated by three additional E atoms and H. The compounds AeE2H2 are classified aspolyanionic hydrides. The peculiar feature of polyanionic hydrides is the incorporation of H in a polymericanion where it acts as a terminating ligand. Polyanionic hydrides provide unprecedented arrangementswith both E-E and E-H bonds. The hydrogenation of AeE2 to AeE2H2 takes place at low reactiontemperatures (around 200 C), which suggests that the polyanion of the polar intermetallics ([E2]2-) isemployed as precursor.
m1, Z = 1, SrGa2H2/D2: a = 4.4010(4)/4.3932(8) Å, c = 4.7109(4)/4.699(1) Å; BaGa2H2/D2: a =4.5334(6)/4.5286(5) Å, c = 4.9069(9)/4.8991(9) Å). The three hydrides SrAl2H2, SrGa2H2, and BaGa2H2decompose at around 300 C at atmospheric pressure. First-principles electronic structure calculationsreveal that H is unambiguously part of a two-dimensional polyanion [E2H2]2- in which each E atom istetrahedrally coordinated by three additional E atoms and H. The compounds AeE2H2 are classified aspolyanionic hydrides. The peculiar feature of polyanionic hydrides is the incorporation of H in a polymericanion where it acts as a terminating ligand. Polyanionic hydrides provide unprecedented arrangementswith both E-E and E-H bonds. The hydrogenation of AeE2 to AeE2H2 takes place at low reactiontemperatures (around 200 C), which suggests that the polyanion of the polar intermetallics ([E2]2-) isemployed as precursor.