Enraf–Nonius CAD-4 diffractometer	1067 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.058
graphite	θmax = 25.3°, θmin = 1.3°
ω/2θ scans	h = 0→7
Absorption correction: ψ scan (North et al., 1968)	k = 0→10
Tmin = 0.957, Tmax = 0.985	l = −19→19
1915 measured reflections	3 standard reflections every 200 reflections
1757 independent reflections	intensity decay: 1%