Transformation of Ammonium Dicyanamide into Dicyandiamide in the Solid
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- 作者：Barbara Jü ; rgens ; Henning A. Hö ; ppe ; Elisabeth Irran ; and Wolfgang Schnick
- 刊名：Inorganic Chemistry
- 出版年：2002
- 出版时间：September 23, 2002
- 年：2002
- 卷：41
- 期：19
- 页码：4849 - 4851
- 全文大小：114K
- 年卷期：v.41,no.19(September 23, 2002)
- ISSN：1520-510X
文摘
Ammonium dicyanamide NH4[N(CN)2] was synthesized throughaqueous ion exchange. The crystal structure was investigated bysingle-crystal X-ray diffraction (P21/c, a = 378.67(6) pm, b =1240.9(3) pm, c = 911.84(14) pm, 
= 91.488(18)
, Z = 4). Itderives from the CsCl structure type. Medium strong hydrogenbonds between NH4+ and [N(CN)2]- ions are indicative of theobserved formation of dicyandiamide H4C2N4 during heating.According to DSC and temperature-dependent X-ray powderdiffractometry, this isomerization is exothermic and occurs between102 and 106 C in the solid. The reaction represents the isolobalanalogue to the classical synthesis of urea by heating NH4OCN.While other alkali and alkaline earth dicyanamides undergotrimerization or polymerization of their anions during heating,ammonium dicyanamide thus shows a different reactivity.
= 91.488(18), Z = 4). Itderives from the CsCl structure type. Medium strong hydrogenbonds between NH4+ and [N(CN)2]- ions are indicative of theobserved formation of dicyandiamide H4C2N4 during heating.According to DSC and temperature-dependent X-ray powderdiffractometry, this isomerization is exothermic and occurs between102 and 106 C in the solid. The reaction represents the isolobalanalogue to the classical synthesis of urea by heating NH4OCN.While other alkali and alkaline earth dicyanamides undergotrimerization or polymerization of their anions during heating,ammonium dicyanamide thus shows a different reactivity.