Hydrothermal Synthesis of Lithium Zinc Phosphates: Structural Investigation of Twinned α-Li4Zn(PO4)2 and a High Temperature Polymorph β-Li4Zn(PO4)2

✍ Scribed by T.R. Jensen; R.G. Hazell; A. Nørlund Christensen; J.C. Hanson

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 381 KB
• Volume: 166
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2002.9602

✦ Synopsis

The system LiOH:Zn(NO 3 ) 2 :H 3 PO 4 :H 2 O was investigated using hydrothermal synthesis techniques in the temperature range 201CoTo6021C and pressure range, 1opo2:8 kbar, and the crystallization fields of some lithium zinc orthophosphates are reported. Small crystals of a twinned lithium zinc phosphate, a-Li 4 Zn(PO 4 ) 2 were prepared and a structural investigation was performed using synchrotron X-ray diffraction: monoclinic, space group P2 1 =a;

The refinement gave RðFÞ¼ 0:042 and wRðF 2 Þ ¼ 0:068 based on 968 independent reflections and 616 observed,

. The cations are tetrahedrally coordinated to oxygen, and the structure can be viewed as layers of regular ZnO 4 and PO 4 tetrahedra interconnected by more distorted LiO 4 tetrahedra. Thermal investigation using in situ powder X-ray diffraction in the temperature range 201CoTo9001C was performed. The reversible phase transition a-b-Li 4 Zn(PO 4 ) 2 was observed in agreement with previous investigations. A powder pattern measured at T=9001C was indexed with a triclinic unit cell: space group P % 1; a ¼ 5:173ð3Þ ( A, b ¼ 7:97ð1Þ ( A, c ¼ 9:92ð1Þ ( A, a ¼ 80:9ð1Þ1; b ¼ 126:8ð1Þ1 and c ¼ 106:0ð1Þ1; V ¼ 319:8ð7Þ ( A 3 and Z ¼ 2: The linear thermal expansion of aand b-Li 4 Zn(PO 4 ) 2 are extracted from powder diffraction data in the temperature range RT to 9001C.