TY - JOUR
T1 - Hexakis(urea-jO)zinc(II) dinitrate at 110 and 250 K: uniaxial negative thermal expansion
AU - Smeets, S.
AU - Lutz, M.
PY - 2011
Y1 - 2011
N2 - The crystal structure of the title compound, [Zn{CO(NH2)2}6]-
(NO3)2, has been determined at 110 and 250 K. The structure
is stabilized by 12 individual hydrogen bonds, both intra- and
intermolecular. Analysis of the thermal expansion tensor,
based on unit cells determined over a temperature range of
180 K, shows uniaxial compression in the direction of the b
axis during warming. The hydrogen bonds form layers
perpendicular to this axis and these layers are connected by
coordinative bonds parallel to the axis. As expected, the
intermolecular hydrogen bonds expand during warming.
Surprisingly, the coordinative bonds contract, accompanied
by changes in the O—Zn—O angles. Overall, this behaviour
can be described as an accordion-like effect.
AB - The crystal structure of the title compound, [Zn{CO(NH2)2}6]-
(NO3)2, has been determined at 110 and 250 K. The structure
is stabilized by 12 individual hydrogen bonds, both intra- and
intermolecular. Analysis of the thermal expansion tensor,
based on unit cells determined over a temperature range of
180 K, shows uniaxial compression in the direction of the b
axis during warming. The hydrogen bonds form layers
perpendicular to this axis and these layers are connected by
coordinative bonds parallel to the axis. As expected, the
intermolecular hydrogen bonds expand during warming.
Surprisingly, the coordinative bonds contract, accompanied
by changes in the O—Zn—O angles. Overall, this behaviour
can be described as an accordion-like effect.
U2 - 10.1107/S0108270111000023
DO - 10.1107/S0108270111000023
M3 - Article
SN - 0108-2701
VL - 67
SP - m50-m55
JO - Acta Crystallographica. Section C, Crystal Structure Communications
JF - Acta Crystallographica. Section C, Crystal Structure Communications
ER -