کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1330501 | 1500124 | 2012 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Ternary CaCu4P2-type pnictides AAg4Pn2 (A=Sr, Eu; Pn=As, Sb) Ternary CaCu4P2-type pnictides AAg4Pn2 (A=Sr, Eu; Pn=As, Sb)](/preview/png/1330501.png)
Four ternary pnictides AAg4Pn2 (A=Sr, Eu; Pn=As, Sb) were prepared by reactions of the elements at 850 °C and their crystal structures were determined from single-crystal X-ray diffraction studies. These silver-containing pnictides AAg4Pn2 adopt the trigonal CaCu4P2-type structure (Pearson symbol hR21, space group R3̄m, Z=3; a=4.5555(6) Å, c=24.041(3) Å for SrAg4As2; a=4.5352(2) Å, c=23.7221(11) Å for EuAg4As2; a=4.7404(4) Å, c=25.029(2) Å for SrAg4Sb2; a=4.7239(3) Å, c=24.689(2) Å for EuAg4Sb2), which can be derived from the trigonal CaAl2Si2-type structure of the isoelectronic zinc-containing pnictides AZn2Pn2 by insertion of additional Ag atoms into trigonal planar sites within [M2Pn2]2− slabs built up of edge-sharing tetrahedra. Band structure calculations on SrAg4As2 and SrAg4Sb2 revealed that these charge-balanced Zintl phases actually exhibit no gap at the Fermi level and are predicted to be semimetals.
SrAg4As2 and related pnictides adopt a CaCu4P2-type structure in which additional Ag atoms enter trigonal planar sites within slabs built from edge-sharing tetrahedra.Figure optionsDownload as PowerPoint slideHighlights
► AAg4Pn2 are the first Ag-containing members of the CaCu4P2-type structure.
► Ag atoms are stuffed in trigonal planar sites within CaAl2Si2-type slabs.
► Ag–Ag bonding develops through attractive d10–d10 interactions.
Journal: Journal of Solid State Chemistry - Volume 192, August 2012, Pages 325–330