The salt metathesis reaction involving a diamine-based antimony chloride precursor with sodium arsaethynolate in the presence of PMe3 leads to the formation of stibanyl-functionalized PMe3-arsinidene (2). Detailed analyses through single-crystal X-ray diffraction and density functional theory of 2 confirm the presence of covalent Sb-As bonds and reveal its polarized nature with a multiple-bond character. In contrast to the formation of complex 2, substituting PMe3 with xylyl isocyanide or 1,3-diisopropyl-4,5-dimethyl-imidazolin-2-ylidene (IiPr) produces an isocyanide-arsinidene adduct (3) and an IiPr-arsaketene complex (4), respectively. Furthermore, the related reactions of precursor 1 with sodium phosphaethynolate yield both a stibanyl-phosphaketene (5) and a stibanyl-functionalized IiPr-phosphaketene adduct (6).