The synthesis and properties of eight new hydroxamic acids derived from alpha-phenylstyrylacrylic acids are described. These hydroxamic acids, which are crystalline compounds, were characterized by their ultraviolet, infrared, and NMR spectra. The purity was checked by HPLC and HPTLC. The nonaqueous titrations and alkaline hydrolysis are reported. Thermodynamic ionization constants at (25 and 35 +/- 0.1) degrees C are determined. Preliminary studies show that these acids form a chloroform-extractable violet complex with vanadium(V) in 6 M hydrochloric acid solutions.