1·The attachment of a group to a central metallic agent such as iron with two valences to form a heterocyclic ring.
一种基与中心金属离子(如二价铁离子)结合，形成杂环。
2·Structute of nitrogen heterocyclic ring quaternary ammonium salt cationic surfactants was identi fied by mass spectrography, nuclear magnetic resonance spectra, infrared spectra and etc.
用质谱法、核磁共振波谱法、红外光谱法等，确定了未知氮杂环季铵盐型阳离子表面活性剂的结构。
3·An organic coordination (complexing) compound in which the metal ion is bound to atoms of nonmetals, e. g. nitrogen, carbon, or oxygen, to form a heterocyclic ring having coordinate covalent bonds.
一种配位(络合)化合物，其中的金属离子与氮、碳或氧等非金属原子结合生成有配位共价键的杂环。
4·Triazine is a type of heterocyclic organic compounds, it is important to ring nitrogen organic chemical raw materials.
是一种三嗪类含氮杂环有机化合物，重要的氮杂环有机化工原料。
5·It is a heterocyclic compound, containing a pyridine ring; its chemical formula is C10H14N. Nicotine is the chief addictive ingredient (see drug addiction) in cigarettes and cigars and in snuff.
尼古丁为杂环化合物，含啶环，化学式为C10H14N，是纸烟、雪茄和鼻烟中的主要上瘾成分。
6·This article reviews the ring opening reaction of five membered nitrogen containing heterocyclic compounds.
综述了近年来各种五元氮杂环的开环反应及其在有机合成中的应用。
7·Purine: Any of a class of heterocyclic compounds with a two-ring structure composed of carbon and nitrogen atoms.
嘌呤：嘌呤是对由碳、氮原子组成的双环结构的杂环化合物的统称。