It has been shown that ammonia and deuterated ammonia react with dimethylchloroarsine to give the respective arseno-ammonium chloride. The dialkylchloroarsines and diarsines react with ammonia-chloramine mixtures to form R4As2N2-HCl (R = CH3 or C2H5) and [(C6H5)2AsN]3·HCl. Physical properties and mass spectral data suggest that (CH3)4As2N2-HCl is a hydrochloride intermediate to an arsenonitrile, while (C2H5)4As2N2HCl is a multiple arsenic-nitrogen bonded polymer containing arsenic-chlorine bonds. The results of the diarsine reactions suggest that arsenic-arsenic bonds are cleaved and give the same products as those obtained by the analogous reaction with dimethyl- or diphenylchloroarsines. The formation of tris(diethylarsino)amine is difficult to explain by an acceptable reaction path. The crystal structure of 2, 2, 4, 4, 6, 6-hexaphenylcyclotriarsazene, [(C6H5)2AsN]3, has been determined from three-dimensional X-ray data collected with an automated diffractometer by use of nickel-filtered copper radiation. The compound crystallizes in the triclinic space group PI with cell dimensions a=9. 713(1)Å, b = 11. 825 (2) Å, c = 15. 645 (2) Å, α = 67. 72 (1)°, β = 93. 49 (1)c, 7= 105. 79 (1)°, and Z = 2. The observed and calculated densities are 1. 51 and 1. 515 g/cm3, respectively. The structure was refined by least-squares calculations to a conventional R index of 0. 061 for 3818 independent intensities. The As3N3 ring of the molecule is slightly puckered. The six As-N bond distances appear to be equivalent with an average value of 1. 758 (4) Å. The structure is discussed relative to that of ](C6H5)2AsN]4. The mass spectral data for [(C6H5)2AsN]4 show As4N4 ring opening with formation of [(C6H5)2AsN]3. The possible fragmentation mechanisms suggested by the metastable peaks are discussed. © 1973, American Chemical Society. All rights reserved.