Alphabetical List of Class Names starting with U, V, W, X, Y and Z

ulosonic acids
ureides
urethanes (urethans)
uronic acids
uronium salts

verdazyl radicals
vinyl carbenes
vinylic cations
vinylic groups
vinylidenes
viologens

Wheland intermediates
Wittig reagents

xanthates
xanthene dyes
xanthic acids
xanthophylls
xylylenes

ylides
ynamines
ynols

zwitterionic compounds/zwitterions