Synthesis, characterization and crystal structure of a novel Strandberg-type polyoxoselenomolybdate Rb{sub 4}[Se{sub 2}Mo{sub 5}O{sub 21}]{center_dot}2H{sub 2}O

Graphical abstract: Crystal structure of Rb{sub 4}[Se{sub 2}Mo{sub 5}O{sub 21}]{center_dot}2H2O. Highlights: Black-Right-Pointing-Pointer Synthesis of the first Strandberg-type polyoxoselenomolybdate Rb{sub 4}[Se{sub 2}Mo{sub 5}O{sub 21}]{center_dot}2H{sub 2}O. Black-Right-Pointing-Pointer Characterization of the novel compound. Black-Right-Pointing-Pointer Chirality of the space group C2 of compound implies that it is expected to have nonlinear optical (NLO) properties -- Abstract: An inorganic compound formulated as Rb{sub 4}[Se{sub 2}Mo{sub 5}O{sub 21}]{center_dot}2H{sub 2}O (1) has been isolated by conventional solution method and structurally characterized by single-crystal X-ray diffraction methods, scanning electron microscopy (SEM), powder XRD, IR, UV-vis spectra, and cyclic voltammetry measurements. This compound crystallizes in the monoclinic system, space group C2 with unit a = 19.701 (3) Angstrom-Sign , b = 10.296 (2) Angstrom-Sign , c = 12.134 (4) Angstrom-Sign , {beta} = 106.96 (2) Degree-Sign and Z = 4. The crystal structure of (1) is built up from a Strandberg clusters connected through hydrogen-bonding interactions into a three-dimensional supramolecular network.