  Let $X$ be a complete $\mathbb{Q}$-factorial toric variety. We explicitly
describe the space $H^2(X,T_X)$ and the cup product map $H^1(X,T_X)\times
H^1(X,T_X)\to H^2(X,T_X)$ in combinatorial terms. Using this, we give an
example of a smooth projective toric threefold for which the cup product map
does not vanish, showing that in general, smooth complete toric varieties may
have obstructed deformations.
