K3Ln[OB(OH)2]2[HOPO3]2 (Ln=Yb, Lu): Layered rare-earth dihydrogen borate monohydrogen phosphates

Two isotypic layered rare-earth borate phosphates, K{sub 3}Ln[OB(OH){sub 2}]{sub 2}[HOPO{sub 3}]{sub 2} (Ln=Yb, Lu), were synthesized hydrothermally and the crystal structures were determined by single-crystal X-ray diffraction (R3-bar , Z=3, Yb: a=5.6809(2) A, c=36.594(5) A, V=1022.8(2) A{sup 3}, Lu: a=5.6668(2) A, c=36.692(2) A, V=1020.4(1) A{sup 3}). The crystal structure can be described in terms of stacking of Glaserite-type slabs consisting of LnO{sub 6} octahedra interlinked by phosphate tetrahedra and additional layers of [OB(OH){sub 2}]{sup -} separated by K{sup +} ions. Field and temperature dependent measurements of the magnetic susceptibility of the Yb-compound revealed Curie-Weiss paramagnetic behavior above 120 K ({mu}{sub eff}=4.7 {mu}{sub B}). Magnetic ordering was not observed down to 1.8 K. - Graphical abstract: Two isotypic layered rare-earth borate phosphates, K{sub 3}Ln[OB(OH){sub 2}]{sub 2}[HOPO{sub 3}]{sub 2} (Ln = Yb, Lu), were synthesized hydrothermally and the crystal structures were determined by single-crystal X-ray diffraction. The structure can be described by stacking of Glaserite-type slabs and dihydrogen borate layers separated by potassium cations. Highlights: > First hydrothermal synthesis of rare-earth borate phosphates. > Instead of microcrystalline powders the synthesis of single crystals was achieved. > Successful single-crystal X-ray structure determination. > 2D arrangement of magnetic rare-earth ions. > EPR spectrum ofmore » Yb{sup 3+} at 5 K.« less