Facile synthetic access to the isolable, thermally robust AsP(3) molecule has allowed for a thorough study of its physical properties and reaction chemistry with a variety of transition-metal and organic fragments. The electronic properties of AsP(3) in comparison with P(4) are revealed by DFT and atoms in molecules (AIM) approaches and are discussed in relation to the observed electrochemical profiles and the phosphorus NMR properties of the two molecules. An investigation of the nucleus independent chemical shifts revealed that AsP(3) retains spherical aromaticity. The thermodynamic properties of AsP(3) and P(4) are described. The reaction types explored in this study include the thermal decomposition of the AsP(3) tetrahedron to its elements, the synthesis and structural characterization of [(AsP(3))FeCp*(dppe)][BPh(4)] (dppe = 1,2-bis(diphenylphosphino)ethane), 1, selective single As-P bond cleavage reactions, including the synthesis and structural characterization of AsP(3)(P(N((i)Pr)(2))N(SiMe(3))(2))(2), 2, and activations of AsP(3) by reactive early transition-metal fragments including Nb(H)(eta(2)-(t)Bu(H)C horizontal lineNAr)(N[CH(2)(t)Bu]Ar)(2) and Mo(N[(t)Bu]Ar)(3) (Ar = 3,5-Me(2)C(6)H(3)). In the presence of reducing equivalents, AsP(3) was found to allow access to [Na][E(3)Nb(ODipp)(3)] (Dipp = 2,6-diisopropylphenyl) complexes (E = As or P) which themselves allow access to mixtures of As(n)P(4-n) (n = 1-4).