Spectra from a study of the basic copper phosphate minerals: Cornetite, libethenite, and pseudomalachite

The molecular structures of the basic copper phosphate minerals pseudomalachite, libethenite, and cornetite were studied using a combination of infrared emission spectroscopy, infrared absorption, and Raman spectroscopy. Infrared emission spectra of these minerals were obtained over the temperature range 100 to 1000 °C.

The infrared spectra of the three minerals are different, in line with differences in crystal structure and composition. The absorption spectra are similar, particularly in the OH stretching region, but characteristic differences in the bending regions are observed. Differences are also observed in the phosphate stretching and bending regions. The IR emission of the basic copper phosphates studied shows that the minerals are completely dehydroxylated by 550 °C.

Figure 1 shows the infrared absorption spectrum of the hydroxyl-stretching region of (a) pseudomalachite, (b) libethenite, and (c) cornetite. Figure 2 is the infrared emission spectra of the hydroxyl-stretching region of (a) pseudomalachite, (b) libethenite, and (c) cornetite from 100°C to 600° at 50°C intervals. Figure 3 shows the intensity of the hydroxyl stretching vibrations of (a) pseudomalachite, (b) libethenite, and (c) cornetite as a function of temperature. Figure 4 is band centers of the hydroxyl stretching vibrations of (a) pseudomalachite, (b) libethenite, and (c) cornetite as a function of temperature. Figure 5 is bandwidth of the hydroxyl stretching vibrations of (a) pseudomalachite, (b) libethenite, and (c) cornetite as a function of temperature. Figure 6 shows the infrared emission spectra of the 700 to 1700 cm−1 region of (a) pseudomalachite, (b) libethenite, and (c) cornetite from 100 to 600 °C at 50 °C intervals. Figure 7 is the Intensity of the hydroxyl bending vibrations of (a) pseudomalachite, (b) libethenite, and (c) cornetite as a function of temperature. Figure 8 is the peak width of the hydroxyl bending vibrations of (a) pseudomalachite, (b) libethenite, and (c) cornetite as a function of temperature.

采用红外发射光谱学、红外吸收光谱学和拉曼光谱学相结合的方法，对基本铜磷酸矿物假孔雀石、利贝斯替特和科内特进行了一系列分子结构的研究。在100至1000摄氏度的温度范围内，获取了这些矿物的红外发射光谱。三种矿物的红外光谱存在差异，这与它们的晶体结构和组成上的差异相一致。吸收光谱在羟基伸缩区域相似，但在弯曲区域存在典型的差异。在磷酸伸缩和弯曲区域也观察到了差异。研究的基本铜磷酸的IR发射表明，矿物在550摄氏度时完全脱羟基化。图1展示了假孔雀石、利贝斯替特和科内特羟基伸缩区域的红外吸收光谱。图2展示了从100摄氏度至600摄氏度，以50摄氏度为间隔的假孔雀石、利贝斯替特和科内特羟基伸缩区域的红外发射光谱。图3展示了假孔雀石、利贝斯替特和科内特羟基伸缩振动强度随温度变化的关系。图4展示了假孔雀石、利贝斯替特和科内特羟基伸缩振动波带中心随温度变化的关系。图5展示了假孔雀石、利贝斯替特和科内特羟基伸缩振动带宽随温度变化的关系。图6展示了假孔雀石、利贝斯替特和科内特在100至600摄氏度，以50摄氏度为间隔的700至1700厘米^-1区域的红外发射光谱。图7展示了假孔雀石、利贝斯替特和科内特羟基弯曲振动随温度变化的强度。图8展示了假孔雀石、利贝斯替特和科内特羟基弯曲振动峰宽随温度变化的关系。