Synthesis and single crystal structures of ternary phosphides Li4SrP2 and AAeP (A=Li, Na; Ae=Sr, Ba)

✍ Scribed by Yongkwan Dong; Francis J. DiSalvo

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 491 KB
• Volume: 180
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2006.10.033

✦ Synopsis

Two new (NaSrP, Li 4 SrP 2 ) and two known (LiSrP, LiBaP) ternary phosphides have been synthesized and characterized using single crystal X-ray diffraction studies. NaSrP crystallizes in the non-centrosymmetric hexagonal space group P 62m (#189, a ¼ 7.6357(3) A ˚, c ¼ 4.4698(3) A ˚, V ¼ 225.69(2) A ˚3, Z ¼ 3, and R/wR ¼ 0.0173/0.0268). NaSrP adopts an ordered Fe 2 P structure type. PSr 6 trigonal prisms share trigonal (pinacoid) faces to form 1D chains. Those chains define large channels along the [001] direction through edgesharing. The channels are filled by chains of PNa 6 face-sharing trigonal prisms. Li 4 SrP 2 crystallizes in the rhombohedral space group R 3m (#166, a ¼ 4.2813(2) A ˚, c ¼ 23.437(2) A ˚, V ¼ 372.04(4) A ˚3, Z ¼ 3, and R/wR ¼ 0.0142/0.0222). In contrast to previous reports, LiSrP and LiBaP crystallize in the centrosymmetric hexagonal space group P6 3 /mmc (#194, a ¼ 4.3674(3) A ˚, c ¼ 7.9802(11) A ˚, V ¼ 131.82(2) A ˚3, Z ¼ 2, and R/wR ¼ 0.0099/0.0217 for LiSrP; a ¼ 4.5003(2) A ˚, c ¼ 8.6049(7) A ˚, V ¼ 150.92(2) A ˚3, Z ¼ 2, and R/ wR ¼ 0.0098/0.0210 for LiBaP). Li 4 SrP 2 , LiSrP, and LiBaP can be described as Li 3 P derivatives. Li atoms and P atoms make a graphitelike hexagonal layer, 2 1 ½LiP 2À . In LiSrP and LiBaP, Sr or Ba atoms reside between 2 1 ½LiP 2À layers to substitute for two Li atoms of Li 3 P, while in Li 4 SrP 2 , Sr substitutes only between every other 2 1 ½LiP 2À layer.