The VH 2 molecule was found to have Sϭ3/2 and a 4 ⌺ ground state with a zero-field splitting parameter ͉D͉ϭ0.315 cm Ϫ1 . 51 V ͑Iϭ7/2͒ hyperfine splitting was observed in the ESR spectra, but the hydrogen hyperfine was unresolved. The narrowest lines were observed for VD 2 in solid deuterium at ϳ2 K. Efforts to observe VH 4 via ESR were not successful presumably because it could not be prepared in a high enough concentration. The infrared spectra of NbH 2 molecules and their deuterated isotopomers were observed in solid deuterium and rare-gas matrices. NbH 2 was found to be bent at 130°, in accord with theoretical calculations. NbH 2 was not observed in ESR spectra although it presumably has a 4 B 1 ground state; this is attributed to a large ͑Ͼ4 cm Ϫ1 ͒ negative D value. NbH 4 was observed via ESR as a tetragonally distorted (D 2d ) tetrahedral molecule in its 2 B 1 lowest state resulting from a static Jahn-Teller effect. 93 Nb ͑Iϭ9/2͒ and also H hyperfine splittings were observed. A corresponding TaH 4 spectrum was attributed to a similarly distorted tetrahedral Sϭ1/2 molecule.