We present the in-depth determination of the magnetic properties and electronic structure of the luminescent and volatile dysprosium-based single molecule magnet [Dy2(bpm)(fod)6] (Hfod = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione, bpm = 2,2-bipyrimidine).

The [B12 H12](2-) anion shows an extensive substitutional chemistry based on its three-dimensional aromaticity. The replacement of functional groups can be attained by electrophilically induced substitution caused by Brønsted or Lewis acidic electrophiles (e.g. Pt(2+)). Until now, it was impossible to structurally characterize a metal-substituted [B12 H12](2-) cage. When an aqueous solution containing both Bi(3+) cations and [B12 H12](2-) anions was heated, the charge-neutral bismuth undecahydro-closo-dodecaborane BiB12 H11 was obtained, representing a new class of metalated [B12 H12](2-) clusters. The title compound was characterized by single-crystal X-ray diffraction and NMR spectroscopic methods. Compared to the typical B-H bond, the short B-Bi single bond (230 pm) exhibits inverted polarity.

The reaction of Pb[CO3] with an aqueous solution of (H3O)2[B10H10] in an equimolar ratio leads to two lead(II) decahydro‐closo‐decaborate hydrates both as triclinic, pale yellow single crystals. The water‐rich compound with the formula [Pb(H2O)3]2Pb[B10H10]3·5.5H2O crystallizes in the space group P1 (a = 711.72(4), b = 1243.14(8), c = 2064.83(12) pm, α = 81.806(3), β = 83.795(3), γ = 80.909(3)°) with Z = 2. The compound with the lower water content, [Pb(H2O)3]Pb[B10H10]2·1.5H2O, also crystallizes in P1 (a = 718.46(4), b = 1288.75(8), c = 1279.91(8) pm, α = 70.145(3), β = 75.976(3), γ = 80.324(3)°) with Z = 2. Both structures can be described as layered arrangements and contain one Pb2+ cation each, which is only coordinated by the hydridic hydrogen atoms of the hydroborate anions. All the others are primarily surrounded by three water molecules in a non‐planar fashion and additional hydrogen atoms of [B10H10]2– anions. The non‐lead‐bonded crystal water molecules in both structures are all connected via hydrogen bonds to the water molecules, which coordinate the Pb2+ cations, as well as via non‐classical hydrogen bonds to the cluster anions and reside between the layers. The [B10H10]2– anions show only slight distortions from their ideal shape as bicapped square antiprisms.