First, a flame isthe visible, gaseous part of a fire. In this sense, flame does not reallyequate fire although the two words are constantly used interchangeably. Ingeneral, the manifestation of color in a flame is an exceedingly complexprocess. Regardless, what color a particular flame exhibits largely depends ontwo factors: 1) the temperature of the flame and 2) the molecular speciesinside the flame.
我们先看看温度如何影响火焰的颜色 - 如果你们还记得黑体辐射。所有的微观粒子都可以被视为永久的振荡点电荷，可以以一定的频率发射电磁波，也就是光。一些光在可见光范围内发射，可以被人眼捕获。物体的温度越高（假设物体本身没有强烈吸收颜色），则发光越靠近蓝紫色。
Let's see first seehow temperature affects the color of the flame - if you all still rememberblackbody radiation. All microscopic particles can be viewed as eternallyoscillating point charges which can then emit electromagnetic waves, or light,at a certain frequency. Some of the light is emitted in the visible range andcan be captured by human eyes. The higher the temperature of an object(assuming that the object itself is not strongly absorbing color), the moreblue-shifted the light.
例如，电炉大约为1000℃，加热时呈深红色;而白炽灯泡内的钨丝为黄色，温度为3000°C。太阳的表面约为6000℃，因此太阳光进一步蓝移到绿色区域（尽管由于宽的光谱范围而呈现为白色）。
For example, anelectric stove is roughly 1000 °C and is dark red in color when heated; while the tungsten filamentinside an incandescent light bulb is yellow with a temperature of 3000 °C. The surface of the sun is about 6000 °C and thus the sunlight is further blue-shiftedto the green region (although it appears white due to the broad spectralrange).
电炉大约1000度，呈现暗红色
The stoveappears dark-red at 1000 °C.
白炽灯中的钨丝大约3000度，辐射出黄色为主的光.
The tungsten filament emits yellow at 3000 °C.
人体大约37度，辐射出肉眼不可见的红外线.
The human body emits invisible infra-red light at 37 °C.
蜡烛火焰可以基本上被视为黑体辐射现象（尽管主要是烟灰，也就是火焰内部的炭黑细碳粒，作为黑体来辐射）。当蜡烛中燃料的“灰尘颗粒”被加热到1000-1400℃时，这些颗粒开始产生电磁辐射，因此我们习惯看到的熟悉的黄橙色。
The whole blob of acandle flame could be essentially viewed as a blackbody radiation phenomenon(although it is mostly the soot, or the fine carbon particles, inside the flameacting as the blackbody). When the fuel "dust particles" are heatedto 1000-1400 °C, they start to generate EM radiation and thusthe familiar yellow-orange color we are used to seeing.
靠近灯芯的火焰的蓝色部分怎么解释？在这一点上，很容易得出错误的结论：说底部更热，因此黑体辐射进一步蓝移。事实证明，蓝色火焰的温度只有800摄氏度，明显低于1400℃的黄色火焰。有时候有点化学知识但是知识不多的时候乱解释也是很危险的！
What about the bluepart of the flame that is close to the wick? It is very easy to jump to thewrong conclusion at this point to say that the bottom is hotter and thus theblackbody radiation is further blue-shifted. It turns out that the blue flameis only 800 °C in temperature, which is significantly lowerthan the 1400 °C yellow flame. Sometimes it is a dangerouspath to take on if you have some chemistry knowledge but not so much.
那应该如何解释？这是一个更复杂一点的解释。蜡由烃（tīng，“碳”的生母加上“氢”的韵母）分子制成，这意味着它们只含有碳原子和氢原子（如果我们忽略在生产过程中所有可能产生的杂质）。当温度足够高时，烃分子被蒸发到气相并开始分解成碳自由基，然后发射蓝色光。这与Na +和Cu2 +的原子发射光谱（黄色和绿色的火炬）相似，我们在高中学习。像萤火虫的发光一样，这些光属于冷光。
How so? Well, thatis a little more complicated to explain, but I will try my best. Wax is madeout of hydrocarbon molecules, which means they only contain carbon and hydrogenatoms (more or less, if we ignore all possible impurities during production).When the temperature is high enough, the hydrocarbon molecules are vaporizedinto the gaseous phase and start to break down into carbon radicals, which thenemit blue light. This is similar to the atomic emission spectra of Na+and Cu2+ (yellow and green when torched) we learned in high school.Just like fireflies, these light sources are considered "cold".
火烧氯化钠放出黄光
火烧氯化铜放出绿光
在大多数分子中，电子成对地成对以获得额外的稳定性;对于自由基，它们是不配对的，能量更高。碳自由基中电子的这种提高的能量是重要的，因为然后需要更少的能量将电子从碳原子拉到更远的地方。这种降低的能量需求将用于激发配对电子的紫外光变成了用于激发不成对电子的可见区域。
In most molecules,electrons sit in pairs to gain extra stability; for radicals, they are unpairedand higher in energy. This elevated energy of the electron in carbon radicalsis important since it then takes less energy to pull the electron away from thecarbon atom. This lowered energy requirement pushes the otherwise UV light forexciting paired electrons to the visible region for unpaired electrons.
蓝色火焰的分子光谱：主要发射来自碳自由基。
总之，蜡烛火焰的黄色部分主要是由于黑体辐射，而较低的蓝色部分主要是由于碳自由基物质的分子发射的结果。
In summary, theupper yellow part of the candle flame is mostly due to blackbody radiation andthe lower blue part is largely as a result of molecular emission from carbonradical species.
最佳答案是二氰基乙炔，也称为碳氮化亚烷基或丁-2-炔基丁腈（IUPAC国际命名），是具有化学式C 4 N 2的碳和氮的化合物。二氰基乙炔具有线性分子结构，N≡C-C≡C-C≡N（通常缩写为NC4N），具有交替的三重和单个共价键。二氰基乙炔可以看作是两个氢原子被氰化物基团取代的乙炔。在室温下，二氰基乙炔是透明液体，可能会对碳粉和氮气产生爆炸作用。二氰基乙炔在氧气中燃烧时产生5260 K（4990°C，9010°F）的温度，并产生明亮的蓝白色火焰，是任何已知化学反应中温度最高的火焰，几乎接近太阳表面的温度。
This best answer is dicyanoacetylene, also called carbon subnitride or but-2-ynedinitrile (IUPAC), which is a compound of carbon and nitrogen with chemical formula C4N2. It has a linear molecular structure, N≡C−C≡C−C≡N (often abbreviated as NC4N), with alternating triple and single covalent bonds. It can be viewed as acetylene with the two hydrogen atoms replaced by cyanide groups. At room temperature, dicyanoacetylene is a clear liquid. Because of its high endothermic heat of formation, it can explode to carbon powder and nitrogen gas, and it burns in oxygen with a bright blue-white flame at a temperature of 5260 K (4990 °C, 9010 °F), which is the hottest flame of any known chemical reaction.
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