利用金刚石压腔装置和激光加热技术, 在高温高压下对KCl—O2体系进行化学反应研究。 实验中先将样品体系预压到37 GPa, 然后对样品进行激光加热处理, 加热温度(1 800±200) K, 淬火至常温后进行激光拉曼测试。 拉曼测试结果显示KCl—O2体系在高温高压下发生了新奇的化学反应, 生成三方(P-3c1)结构的非传统化合物KCl3、 少量KClO4、 固体Cl2(Cmca)以及可能存在的另外一种非传统化合物KO4。 实验中P-3c1-KCl3高压下测到了11个拉曼振动峰, 基于P-3c1-KCl3第一性原理拉曼光谱的理论计算, 将这11个拉曼振动峰进行振动模式归属。 P-3c1-KCl3在卸压过程中拉曼峰强度逐渐变弱, 于压力小于10 GPa时逐渐分解变成KCl和Cl2, 反映其不能在常压下保存。 KO4在高压下受到金刚石拉曼峰的干扰难以检测到拉曼峰, 而在常压下打开金刚石压腔后测到了KO4的3个拉曼振动峰。 实验显示易吸潮的KO4黑色粉末能够保存到常压。 KCl3和KO4中分别具有带分数负电荷的非线性对称Cl—Cl—Cl聚阴离子链和O—O原子对, 反映高压有利于形成非常规聚阴离子(Cl-3)和阴离子(O-4), 表现出与常压或者低压不一样的化学特性。 实验显示在高压下存在数个不同寻常的化学反应, 通过对反应物和生成物的氧化还原价态分析显示, O得到电子由0价变成负价态, 而Cl失去电子由负价态变成0价或者正价态, 反映高压下O得电子能力强于Cl。 这些新奇的化学反应以及非常规聚氯阴离子化合物P-3c1-KCl3的实验观察为合成具有奇特性质的聚阴离子化合物提供了新的思路。

The chemical reaction of KCl—O2 system was studied under high pressure and high temperature by using the diamond anvil cell and the laser heating technology. The KCl—O2 sample was heated at 37 GPa ［(1 800±200) K］and then the products were measured by Raman technology at ambient temperature. The Raman test results show that the KCl—O2 system undergoes a chemical reaction at high pressure and high temperature, producing a non-conventional compound KCl3 with a trigonal (P-3c1) structure, a small amount of KClO4, solid Cl2 (Cmca), and possibly existing another non-traditional compound KO4. In this experiment, 11 Raman vibration peaks of P-3c1-KCl3 were measured under high pressure. According to the theoretical calculation of the Raman spectrum of P-3c1-KCl3 in the first principle, the 11 Raman vibration peaks were assigned to the vibration modes. The P-3c1-KCl3 gradually weakens on decompression, and decomposes into KCl and Cl2 below 10 GPa, indicating that P-3c1-KCl3 cannot be stored under ambient pressure. It is difficult to detect the Raman peak of KO4for being disturbed by the Raman peak of diamond under high pressure, and the three Raman vibration peaks of KO4 are detected after opening the diamond anvil cell under ambient pressure. Experiments have shown that the moisture-absorbing KO4 black powder can be stored at ambient pressure. The emergence of novel chemical reaction products of KCl3 and KO4 shows that high pressure promotes oxygen and chlorine forming unconventional pair-anions (O—O pair-anions) and polyanions (Cl—Cl—Cl polyanions) with the negative charge of the fraction, indicating that the two elements have unconventional chemical properties under high pressure. Experiments have also shown that there are several unusual chemical reactions under high pressure. The oxidation state of the reactants and products shows that O gains electrons from zero to negative valence, while Cl loses electrons from negative valence to zero or positive valence state, reflecting that O is more electron-friendly than Cl. These novel chemical reactionsprovide a new pathway to synthesize the polyhalide anions compounds that may have exotic properties.