Measurement of Cl and N quadrupole coupling in ClCN

J = 1 ← 0 and J = 2 ← 1 transitions in ³⁵ClCN and ³⁷ClCN were measured using a C-band waveguide spectrometer and phase-locked sources. Parameters obtained from the data are: $\text{B(}{}^{35}\text{ClCN) = 5 970.820 ± 0.010 MHz}$, $\text{B(}{}^{37}\text{ClCN) = 5 847.246 ± 0.008 MHz}$, $\text{eqQ(}{}^{35}\text{Cl) = ?83.26 ± 0.04 MHz}$, $\text{eqQ(}{}^{37}\text{Cl) = ?65.61 ± 0.04 MHz}$ and $\text{eqQ(}{}^{14}\text{N) = ?3.60 ± 0.08 MHz}$.