Isocyanic acid, HNCO, the imide of carbon dioxide, was prepared by reaction of stearic acid and potassium cyanate (KOCN) at 60 °C in a sealed, thoroughly dried reactor. Interestingly, its crystal structure, solved by X-ray single crystal diffraction at 123(2) K, shows a group–subgroup relation for the NCO^– anion to carbon dioxide: (for CO₂, cP12, Pa3̅, a = 5.624(2) Å, 150 K, C–O 1.151(2) Å; for HNCO, oP16, Pca2₁, a = 5.6176(9), b = 5.6236(8), c = 5.6231(7) Å, 123(2) K). Precise positions of H, N, C, and O were determined by DFT calculations with WIEN2k leading to interatomic distances C–O 1.17, C–N 1.22, N–H 1.03, and −N–H···N 2.14 Å, and the interatomic angle N–C–O 171°.

中文翻译：

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异氰酸，HNCO，二氧化碳的酰亚胺的分子结构

硬脂酸和氰酸钾（KOCN）在密闭，充分干燥的反应器中于60°C反应制备异氰酸HNCO（二氧化碳的酰亚胺）。有趣的是，它的晶体结构，在123（2）K通过X射线单晶衍射解决，示出了对于NCO基团子群关系^-阴离子为二氧化碳：（对于CO ₂，厘泊12，帕3，一个= 5.624 （2）Å，150 K，C–O 1.151（2）Å;对于HNCO，oP 16，Pca 2 ₁，a = 5.6176（9），b = 5.6236（8），c= 5.6231（7）Å，123（2）K）。通过DFT计算确定H，N，C和O的精确位置，WIEN2k导致原子间距离C–O 1.17，C–N 1.22，N–H 1.03和-N–H··N 2.14Å，以及原子间夹角N–C–O 171°。