The crystal structure of bromomalonamide, HBrC(CONH2)2, has been determined from MoKadiffractometer data by use of Patterson and Fourier syntheses. The crystals are orthorhombic,Pnma, with cell constants at 22deg;C:aequals;9.487(3) Aring;,bequals;11.294(4) Aring;,cequals;5.885(3) Aring;, rgr;cequals;1.90 g cmminus;3,pmequals; 1.85 g cmminus;3. The value ofR1for 270 observed reflections is 0.029. There are four molecules in the unit cell and onehyphen;half molecule in the asymmetric unit. The bond lengths are Csngbnd;Br, 1.954(5) Aring;; Cdblbnd;O, 1.236(7) Aring;; Csngbnd;N, 1.290(5) Aring;; and Csngbnd;C, 1.522(9) Aring;. The threehyphen;dimensional hydrogen bonding network contains 8hyphen; and 12hyphen;membered rings with N middot;middot;middot; O distances of 2.94(1) and 2.82(1) Aring;, and H middot;middot;middot; O distances of 2.21(7) and 1.85(7) Aring;, respectively; the Nsngbnd;H middot;middot;middot; O angles are 164(7)deg;. A rigid body analysis of the thermal motions indicates that there is a librational motion, dominated by the hydrogen bonding scheme, of about 7deg; about a line joining the amide nitrogens of a molecule.
展开▼
