γ-FOX-7:: Structure of a high energy density material immediately prior to decomposition
γ-FOX-7:: Structure of a high energy density material immediately prior to decomposition
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DOI：
10.1002/prep.200700240
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发表时间：
2007-12-01
影响因子：
1.8
通讯作者：
Welch, Jan M.
中科院分区：
文献类型：
--
作者：
Crawford, Margaret-Jane;Evers, Juergen;Welch, Jan M.
1，1-二氨基-2，2-二硝基乙烯（C2 H4 N4 O 4，FOX-7）是一种新型高能量密度材料，具有低摩擦感度、低撞击感度和高爆轰活化势垒。在这项研究中，以前未知的晶体结构的γ-多晶型的三晶型FOX-7的报道。γ-FOX-7在接近435 K的温度下稳定，直到该化合物在504 K以上分解。首先将α-FOX-7（P2（1）/n，Z=4，a=694.67（7）μ m，B= 668.87（9）μ m，c = 1135.1（1）μ m，P = 90.14（1）度，T=373 K）的单晶转化为β-FOX-7（P2（1）2（1）2（1），Z=4，a=698.6（1）μ m，B = 668.6（2）pm，c = 1168.7（3）pm，T=423 K），然后在450 K下转变成γ-FOX-7的单晶。随后将γ-FOX-7晶体淬火至200 K。γ-FOX-7（P2（1）/n，Z=8，a=1335.4（3）pm，B=689.5（1）pm，c=1205.0（2）pm，β =111.102（8）度，T= 200 K）的结构由四个平面层组成，每个平面层包含在不对称单元中发现的两个晶体学独立的FOX-7分子。
1,1-Diamino-2,2-dinitroethene, C2H4N4O4 (FOX-7), is a novel high energy density material with low friction and impact sensitivity and a high activation barrier to detonation. In this study, the previously unknown crystal structure of the gamma-polymorph of trimorphic FOX-7 is reported. gamma-FOX-7 is stable from similar to 435 K until the compound decomposes just above 504 K. A single crystal of alpha-FOX-7 (P2(1)/n, Z=4, a=694.67(7) pm, b= 668.87(9) pm, c = 1135.1(1) pm, P = 90.14(1)degrees, T=373 K) was first transformed into a single crystal of beta-FOX-7 (P2(1)2(1)2(1), Z=4, a=698.6(1) pm, b = 668.6(2) pm, c = 1168.7(3) pm, T=423 K) and then into a single crystal of gamma-FOX-7 at 450 K. The gamma-FOX-7 crystal was then subsequently quenched to 200 K. The structure of gamma-FOX-7 (P2(1)/n, Z=8, a=1335.4(3) pm, b=689.5(1) pm, c=1205.0(2) pm, beta=111.102(8)degrees, T=200K) consists of four planar layers, each containing two crystallographically independent FOX-7 molecules found in the asymmetric unit.