<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The title compound (dap: 1, 2‐diaminopropane) is synthesized by hydrothermal reaction of Na<sub>10</sub>[A‐α‐SiW<sub>9</sub>O<sub>34</sub>], CuCl<sub>2</sub>, YCl<sub>3</sub>, dap, and HCl in aqueous solution (autoclave, 160 °C, 5 d, 24% yield).</p> </abstract>