Not like the others: A molecular palladium oxide cluster was formed by self‐assembly of palladium(II) and arsenic(V) using mild reaction conditions. The resulting heteropolypalladate [PdII13AsV8O34(OH)6]8− has a distorted cubic shape and edge lengths of about 1 nm. The thirteen PdII ions retain four‐coordinate square‐planar geometry, in marked contrast to all other known discrete polyoxometalates.

The reaction of K28Li5H7[P8W48O184].92H2O with early lanthanides under hydrothermal and conventional conditions yields novel structures of the molecular formula Ln4(H2O)28K6Li7[K subsetP8W48O184(H4W4O12)2Ln2(H2O)10] congruent with 57H2O, Ln = La (1), Ce (2, 2a), Pr (3), Nd (4), in which the central cavity of the precursor anion is occupied by lanthanide cations and H4W4O12 moieties. The new heteropolyanions were characterized by elemental analysis, infrared spectroscopy, 31P NMR, and X-ray crystallography. All of the crystals are monoclinic, space group C2/m, with lattice constants (A, Epsilon) a = 33.061(3), b = 30.986(3), c = 15.1649(13), beta = 103.607(2), (1); a = 33.0577(16), b = 31.0562(15), c = 15.2320(7), beta = 104.015(2), (2); a = 33.0577(16), b = 31.0562(15), c = 15.2320(7), beta = 104.015(2), (2a); a = 33.007(2), b = 31.060(2), c = 15.2129(10), beta = 104.0140(10), (3); a = 32.913(19), b = 31.155(18), c = 15.135(9), beta = 103.495(11), (4); and Z = 2.