1,3-Dibromo­azulene

In the structure of 1,3-dibromo­azulene, C₁₀H₆Br₂, the planar mol­ecule sits on a crystallographic mirror plane. The Br atoms are attached to the five-membered ring adjacent to the ring fusion. Head-to-tail charge-charge inter­actions due to partial positive charges on ring H atoms and partial negative charges within the aromatic ring system attract adjacent 1,3-dibromo­azulene mol­ecules together. This causes them to arrange themselves in a zigzag pattern that allows close packing of the oppositely charged groups.

1,3-Diiodo­azulene

In the structure of 1,3-diiodo­azulene, C₁₀H₆I₂, as expected, the mol­ecule is planar. Also observed are short contacts between I atoms and between I and ring C atoms. The crystal structure of this compound exhibits two sets of parallel layers, nearly perpendicular to each other. The layers are formed by charge-charge inter­actions between some I atoms and nearby seven-membered rings of mol­ecules in an adjacent layer. The packing is also affected by attractive dispersion forces between I atoms in adjacent layers.

Sodium tris­(acetyl­acetonato-κ²O,O′)­manganese(II)

In the title compound, Na[Mn(C₅H₇O₂)₃], the manganese(II) ions are each coordinated by six O atoms from three different acetylacetonate ligands in a trigonal prismatic geometry. The octahedrally coordinated Na cations are sandwiched between two adjacent [Mn(acac)₃]⁻ units (acac is acetyl­acetonate). The three crystallographically distinct Mn cations are each located on a crystallographic threefold rotation axis. Two Na cations are also located on special positions with site symmetry 3 and two further Na cations occupy special positions with site symmetry .