<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Single crystals of the title compound are prepared by solid state reaction of Na<sub>2</sub>CO<sub>3</sub>, Mn(OAc)<sub>2</sub>, NH<sub>4</sub>H<sub>2</sub>PO<sub>4</sub>, and KF (alumina crucible, 1153 K, 40 h).</p> </abstract>