Gallaphosphene L(Cl)GaPGaL (2; L=HC[C(Me)N(2,6‐i‐Pr₂C₆H₃)]₂), which is synthesized by reaction of LGa(Cl)PCO (1) with LGa, reacts with [Na(OCP)(dioxane)_2.5] to LGa(OCP)PGaL (3), whereas chloride abstraction with LiBAr^F₄ yields [LGaPGaL][BAr^F₄] (4; BAr^F₄=B(C₆F₅)₄). 4 represents a heteronuclear analog of the allyl cation according to quantum chemical calculations. Remarkably, 2 reversibly reacts with CO₂ to yield L(Cl)Ga−P[μ‐C(O)O]₂GaL (5), while reactions with acetophenone and acetone selectively give compounds 6 and 7 by C(sp³)−H bond activation.

Well-defined germylene cations [(i-Bu)₂ATI]GeOTf (4) and [(i-Bu)₂ATIGe][GaCl₄] (5) are isolated, and the catalytic utility of compound 4 for the hydroboration of a variety of aldehydes and ketones is reported (ATI = aminotroponiminate).

The first Sn^I diradical [(ADC^Ph)Sn]₂ (4) based on an anionic dicarbene (ADC^Ph={CN(Dipp)}₂CPh; Dipp=2,6‐iPr₂C₆H₃) scaffold has been isolated as a green crystalline solid by KC₈ reduction of the corresponding bis‐chlorostannylene [(ADC^Ph)SnCl]₂ (3). The six‐membered C₄Sn₂‐ring of 4 containing six π‐electrons shows a diatropic ring current, thus 4 may also be regarded as the first 1,4‐distannabenzene derivative. DFT calculations suggest an open‐shell singlet (OS) ground state of 4 with a remarkably small singlet–triplet energy gap (ΔE_OS–T=4.4 kcal mol⁻¹), which is consistent with CASSCF (ΔE_S–T=6.6 kcal mol⁻¹ and diradical character y=37 %) calculations. The diradical 4 splits H₂ at room temperature to yield the bis‐hydridostannylene [(ADC^Ph)SnH]₂ (5). Further reactivity of 4 has been studied with PhSeSePh and MeOTf.

A triflatostannylene [L ^† Sn][OTf] ( 2 ) is found to be an efficient catalyst with low-valent main-group element for the hydroboration of aldehydes and ketones.