-azine / heterocyclic compound containing nitrogen in their ring such as pyridine 吡啶[bi3 ding4] C5H5N, pyrazine 噠嗪|哒嗪[da1 qin2] C4H4N2 or pyrimidine 嘧啶[mi4 ding4] C4H4N2
The four tones
Your cookie choices
This site is funded by advertising. With your agreement, Google AdSense sets cookies to display personalised ads and Google Analytics measures traffic. Until you agree, neither script is loaded and nothing is stored on your device. You can change your mind at any time from the footer.
This site is funded by advertising. Google AdSense and Google Analytics set cookies to display ads and measure traffic. You can refuse them — now, or later from the footer.
This site is funded by advertising. Google AdSense and Google Analytics set cookies to display ads and measure traffic. You may opt out of the sale and sharing of your personal information at any time.
This site uses Google cookies — AdSense for advertising, Analytics for traffic measurement. You can refuse them.
