  Using the MALDI-TOF spectroscopy method, clusters of non-stoichiometric
tantalum oxychlorides formed as a result of hydrolysis of nanoscale reaction
products of tantalum pentachloride with acetylene and of interaction with
oxygen and air moisture in the process of sample preparation were studied. The
formation of oxychloride clusters containing from 2 to 15 tantalum atoms is
shown. Quantum chemical calculations of the structure and relative
thermodynamic stability of the possible isomers are carried out. The stability
of cage Ta structures connected by oxygen bridges with significant contribution
of metal-metal bond is established
