The J = 1 <- J = 0 and J = 2 <- J = 1 rotational transitions of platinum monocarbide, PtC, have been recorded using the separated field pump/probe microwave optical double resonance technique and analyzed to determine the fine and hyperfine parameters for the X-1 Sigma(+)(v = 0) state. The Pt-195 (I = 1/ 2) nuclear spin-rotation interaction parameter, C-I(eff), was determined to be +0.138(6) MHz. A comparison with other Pt-containing molecules and a proposed molecular orbital correlation diagram is given. (C) 2012 Elsevier B. V. All rights reserved.