Vanadium

Isotope	Atomic mass (Da)	Isotopic abundance (amount fraction)
⁵⁰V	49.947 156(3)	0.002 50(10)
⁵¹V	50.943 957(3)	0.997 50(10)

In its 1961 report, the Commission accepted A_r(V) = 50.942 based on mass-spectrometric data, and in 1969 recommended a more precise A_r(V) = 50.9414(3). A number of determinations of the isotopic composition of vanadium have since been considered. As a result, in 1977 the Commission refined A_r(V) to 50.9415(1). The isotopic composition of vanadium from five chondritic meteorites has been shown identical within experimental error to the terrestrial diabase W-1 and a laboratory standard.

Two stable isobars, ⁵⁰Ti and ⁵⁰Cr, are the immediate neighbours in the chart of nuclides, to ⁵⁰V, whose β+ and β- decay modes are, therefore, predictable. The nuclear angular momentum of ⁵⁰V, however, is high but consistent with long half-lives, evidently too long to be readily observed. The isobars render the mass-spectrometric determination of the abundance of the isotope ⁵⁰V subject to careful chemical determination of the trace presence of Ti and Cr.

SOURCE Atomic weights of the elements: Review 2000 by John R de Laeter et al. Pure Appl. Chem. 2003 (75) 683-800
© IUPAC 2003

CIAAW

Vanadium
A_r(V) = 50.9415(1) since 1977

The name derives from the Scandinavian goddess of love and beauty, Freyja Vanadis, because of its many beautiful multi-coloured compounds. Vanadium was discovered by the Swedish physician and chemist Nils-Gabriel Sefström in 1830.
Vanadium had originally been discovered by the Spanish mineralogist Andres Manuel del Rio y Fernandez in 1801, who named it erythronium, after the plant of that name whose flowers have many beautiful colours. Del Rio later decided that it was really chromium in his lead sample. Vanadium metal was first isolated by the English chemist Henry Enfield Roscoe in 1869.