Enraf–Nonius CAD-4 diffractometer	2367 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.021
graphite	θmax = 26.0°, θmin = 1.2°
ω/2θ scans	h = −21→0
Absorption correction: ψ scan (North et al., 1968)	k = 0→7
Tmin = 0.866, Tmax = 0.964	l = −20→21
3659 measured reflections	200 standard reflections every 3 reflections
3539 independent reflections	intensity decay: 1%