https://doi.org/10.1351/goldbook.A00452
AsH3 and compounds derived from it by substituting one, two or three hydrogen atoms by hydrocarbyl groups: R3As, RAsH2, R2AsH, R3As (R ≠ H) are called primary, secondary and tertiary arsines, respectively. A specific arsine is preferably named as a substituted arsane, e.g. CH3CH2AsH2 ethylarsane.
See:
arsanes