Structure of caesium dicyanamide

Experimental. The crystals of the title compound were prepared a s very thin plates by dropping a freshly obtained (through ion ex.change) aqueous solution of dicyanamide [NH(CN)2] into an aqueous solution of CszCOa, and then allowing water to evaporate at ambient temperature. Dm by flotation in C2H4Br2/CH212. Crystal 0.55 x 0.40 × 0.04 mm was cut from a larger one, and placed in a capillary. Syntex P2~ diffractometer, lattice parameters from 0108-2701/91/102198-02503.00 15 reflections with 20 between 18 and 28 ° (Mo Ka), variable w/20 scan, 4 3o-(/) and of which 1012 were unique, Rint (after absorption corrections) = 0.0335. Absorption corrections with DIFABS (Walker & Stuart, 1983) between 0.620 and 1.396. Structure was solved with SHELX86 (Sheldrick, 1986) and refined with SHELX76 (Sheldrick, 1976). Neutral atom scattering factors from International Tables for X-ray Crystallography (1974, Vol. IV), real and imaginary components of anomalous dispersion included for all atoms. Final full-matrix least-squares refinement based on F with all atoms anisotropic, R = 0-0500, © 1991 International Union of Crystallography P. S T A R Y N O W l C Z 2199 Tab le 1. Atomic coordinates and equivalent U factors (A 2) Ucq = (I/3)Z, Zi Uua,*aj*a,.a j. x y z Ucq Csl 0 -00191 (I) 0'25 00660 (3) Cs2 0-5 01219 (1) 025 0'0668 (3) N! 0-0969 (13) 01733 (10) 0-0696 (13) 0'084 (3) N2 0'2249 (14) 0'3226 (10) 02446 (15) 0090 (3) N3 0-1801 (12) 0-4131 (10) 0-4814 (13) 0-082 (3) CI 01511 (12) 0-2464 (9) 01577 (12) 0-063 (3) C2 0'1941 (12) 0'3676 (8) 03710 (14) 0'065 (3) Tab le 2. Bonds lengths (A) and angles (o) & the dicyanamide anion N I C I 1-18 (2) N2--C2 1-31 (2) C I N 2 1.26 (2) C2-N3 1-13 (2)