The word precipitins is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 21
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (27 words)
cistern, citrine, cretins, crispen, inciter, incites, inspect, inspire, irenics, nippers, nippier, pectins, picrite, pincers, pitiers, princes, pterins, sericin, snipper, snippet, spicier, spinier, tiepins, tippers, tippier, tipsier, triceps