为什么画中圣母的蓝曾比黄金还贵？
Why was the blue of Madonnas once more precious than gold?
天然群青取自青金石，矿少难提炼，合成群青（1828）出现前极昂贵；现在用高岭土、硫和纯碱即可合成。
Natural ultramarine came from rare lapis lazuli and was precious before synthetic ultramarine (1828); now made from kaolin, sulfur and soda ash.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Theodore Gray,《Molecules: The Elements and the Architecture of Everything》,Black Dog & Leventhal,2014
Theodore Gray, Molecules, Black Dog & Leventhal, 2014
独立核验依据 · Independent verification: 核验依据 2 ISBN 9780665590955 (2002)
#群青 #青金石 #合成
为什么有些衣服洗几次就掉色，有些却不掉？
Why do some clothes fade after a few washes but others don't?
染料若只靠物理吸附在纤维表面就容易脱落；能与纤维形成化学键或深入内部的染料结合更牢，耐洗耐晒。
Dyes merely adsorbed on the surface wash out easily; those bonded chemically or embedded in the fiber resist washing and light.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Theodore Gray,《Molecules: The Elements and the Architecture of Everything》,Black Dog & Leventhal,2014
Theodore Gray, Molecules, Black Dog & Leventhal, 2014
独立核验依据 · Independent verification: 核验依据 2 ISBN 9780665590955 (2002)
#染色 #牢度 #纤维
偶氮染料分子中,改变芳环取代基(如在对位引入 -NO2 或 -NH2)为什么能够调节染料的颜色?
For azo dye molecules, how does changing ring substituents, for example introducing para -NO2 or -NH2 groups, tune the dye color?
供电子或吸电子取代基改变共轭体系的电荷分布,从而移动 π→π* 跃迁和分子内电荷迁移跃迁的能量。吸电子基与供电子基协同构成推拉电子结构时,跃迁能隙缩小,最大吸收波长红移,颜色加深;相互作用较弱的取代基影响有限,通常只带来小幅谱带位移或色调微调。工业上正是按这一规律,以不同取代模式设计出黄、橙、红、蓝等系列偶氮染料。
Donating or withdrawing substituents redistribute charge across the conjugated framework, shifting the energies of pi-pi* and intramolecular charge-transfer transitions. When an acceptor and a donor act together as a push-pull system, the transition gap narrows, the absorption maximum red-shifts, and the shade deepens; weakly interacting groups exert only modest effects, giving small band shifts or subtle hue adjustments. Dyestuff chemists apply this rule systematically to design azo series spanning yellow, orange, red, and blue shades.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
Zollinger H., Color Chemistry, 3rd ed., Wiley-VCH, 2003, 第 2 章(染料结构与颜色的关系)
Zollinger H., Color Chemistry, 3rd ed., Wiley-VCH, 2003, Ch. 2 (structure-color relationships in dyes)
#偶氮染料 #取代基效应
偶氮染料的颜色从何而来?又为什么在日晒下会慢慢褪掉?
Where does the color of azo dyes come from, and why do they gradually fade under sunlight?
偶氮基把两个芳环连成大的共轭体系,其前线轨道能级差落入可见光区,电子跃迁吸收特定波长后呈现互补色;给电子基团与吸电子基团的推拉效应还会进一步加深色光。日光照射下偶氮键发生顺反异构化并被氧化断裂,共轭通道被切断,吸收峰移出可见区,宏观上就是褪色。
An azo bridge fuses two aromatic rings into one extended conjugated system whose frontier-orbital gap lies in the visible range; after absorbing particular wavelengths the dye shows the complementary color, and donor-acceptor push-pull substitution deepens the shade further. Sunlight drives trans-cis isomerization and eventual oxidative scission of the nitrogen-nitrogen bond, cutting the conjugation so absorption moves out of the visible spectrum—the dye visibly fades.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Bandara H M D, Burdette S C. Photoisomerization in different classes of azobenzene. Chem. Soc. Rev., 2012, 41: 1809-1825
Bandara H M D, Burdette S C. Photoisomerization in different classes of azobenzene. Chemical Society Reviews, 2012, 41: 1809-1825
独立核验依据 · Independent verification: 核验依据 1 DOI 10.1002/chin.201220260
#染料与颜色化学 #偶氮发色体系
永久性染发剂是怎么把头发染色的？
How do permanent hair dyes color hair?
先用碱打开毛鳞片，小分子无色前体渗入皮质，再用氧化剂（过氧化氢）让它们在发丝内偶合成有色大分子，就被锁住了。
Alkali opens the cuticle; tiny colorless precursors enter the cortex and an oxidant (hydrogen peroxide) couples them into colored molecules trapped inside.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Theodore Gray,《Molecules: The Elements and the Architecture of Everything》,Black Dog & Leventhal,2014
Theodore Gray, Molecules, Black Dog & Leventhal, 2014
独立核验依据 · Independent verification: 核验依据 2 ISBN 9780665590955 (2002)
#染发 #氧化 #偶合
为什么蓝草叶子是绿的，染出的布却是蓝的？
Why are indigo plant leaves green but the dyed cloth blue?
蓝草含靛苷，发酵水解得到靛白（隐色体，可溶，黄绿）；布浸入后拿出，靛白被空气氧化成不溶的靛蓝，显现蓝色，这是传统蓝印花布的原理。
Indigo plants contain indican; fermentation yields leuco-indigo (soluble, yellow-green). Fabric soaked then exposed to air oxidizes it to insoluble blue indigo—the traditional vat-dyeing method.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Theodore Gray,《Molecules: The Elements and the Architecture of Everything》,Black Dog & Leventhal,2014
Theodore Gray, Molecules, Black Dog & Leventhal, 2014
独立核验依据 · Independent verification: 核验依据 2 ISBN 9780665590955 (2002)
#靛蓝 #染色 #还原
为什么古代朱砂红得鲜艳却有剧毒？
Why was ancient cinnabar vivid red yet deadly?
朱砂是硫化汞（HgS），色红稳定，用作印泥和壁画红颜料；但含汞，长期接触或加热释放汞蒸气有害。
Cinnabar is mercury sulfide (HgS), a stable vivid red used in seals and murals, but mercury makes it toxic if contacted or heated.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Theodore Gray,《Molecules: The Elements and the Architecture of Everything》,Black Dog & Leventhal,2014
Theodore Gray, Molecules, Black Dog & Leventhal, 2014
独立核验依据 · Independent verification: 核验依据 2 ISBN 9780665590955 (2002)
#朱砂 #硫化汞 #颜料
为什么蓝黑墨水刚写是蓝的干了变黑？
Why is blue-black ink blue when wet but black when dry?
蓝黑墨水含鞣酸与铁盐，初呈蓝黑色，写在纸上被空气氧化后颜色加深转黑，牢固不易褪。
Iron-gall ink contains tannins and iron salts; it writes bluish-black then darkens to black on oxidation, staying permanent.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Theodore Gray,《Molecules: The Elements and the Architecture of Everything》,Black Dog & Leventhal,2014
Theodore Gray, Molecules, Black Dog & Leventhal, 2014
独立核验依据 · Independent verification: 核验依据 2 ISBN 9780665590955 (2002)
#蓝黑墨水 #鞣酸铁 #氧化