Ionothermal Synthesis, Crystal Structure, and Magnetic Study of Co<sub>2</sub>PO<sub>4</sub>OH Isostructural with Caminite Guangmei Wang Martin Valldor Eike T. Spielberg Anja-Verena Mudring 10.1021/ic4029904.s002 https://acs.figshare.com/articles/journal_contribution/Ionothermal_Synthesis_Crystal_Structure_and_Magnetic_Study_of_Co_sub_2_sub_PO_sub_4_sub_OH_Isostructural_with_Caminite/2314480 A new framework cobalt­(II) hydroxyl phosphate, Co<sub>2</sub>PO<sub>4</sub>OH, was prepared by ionothermal synthesis using 1-butyl-4-methyl-pyridinium hexafluorophosphate as the ionic liquid. As the formation of Co<sub>2</sub>PO<sub>4</sub>F competes in the synthesis, the synthesis conditions have to be judiciously chosen to obtain well-crystallized, single phase Co<sub>2</sub>PO<sub>4</sub>OH. Single-crystal X-ray diffraction analyses reveal Co<sub>2</sub>PO<sub>4</sub>OH crystallizes with space group <i>I</i>4<sub>1</sub>/<i>amd</i> (<i>a</i> = <i>b</i> = 5.2713(7) Å, <i>c</i> = 12.907(3) Å, <i>V</i> = 358.63(10) Å<sup>3</sup>, and <i>Z</i> = 4). Astonishingly, it does not crystallize isotypically with Co<sub>2</sub>PO<sub>4</sub>F but rather isotypically with the hydroxyl minerals caminite Mg<sub>1.33</sub>[SO<sub>4</sub>­(OH)<sub>0.66</sub>(H<sub>2</sub>O)<sub>0.33</sub>] and lipscombite Fe<sub>2–<i>y</i></sub>PO<sub>4</sub>(OH) (0 ≤ <i>y</i> ≤ 2/3). Phosphate tetrahedra groups interconnect four rod-packed face-sharing <sub>∞</sub><sup>1</sup>{CoO<sub>6/2</sub>} octahedra chains to form a three-dimensional framework structure. The compound Co<sub>2</sub>PO<sub>4</sub>OH was further characterized by powder X-ray diffraction, Fourier transform–infrared, and ultraviolet–visible spectroscopy, confirming the discussed structure. The magnetic measurement reveals that Co<sub>2</sub>PO<sub>4</sub>OH undergoes a magnetic transition and presents at low temperatures a canted antiferromagnetic spin order in the ground state. 2014-03-17 00:00:00 Co 2PO Isostructural Co 2PO synthesis Co 2PO crystallizes compound Co 2PO