Institut für Virologie im MTZ, TU Dresden, Fetscherstr. 74, D-01307, Dresden, Germany.
Dalton Trans. 2010 Oct 28;39(40):9642-53. doi: 10.1039/c0dt00417k. Epub 2010 Sep 7.
Phosphoric acid in water and heavy water has been studied by Raman and infrared spectroscopy over a broad concentration range (0.00873-1.560 mol kg(-1)) at 23 °C. The vibrational modes of the PO(4) skeleton (C(3v) symmetry) of H(3)PO(4)(aq) and D(3)PO(4)(D(2)O) have been assigned. In addition to the P-O stretching modes a deformation mode has been detected, δPO-H(D) at 1250 and 935 cm(-1), respectively. In addition to the modes of the phosphoric acid and heavy phosphoric acid a mode of the dissociation product H(2)PO(4)(-) and D(2)PO(4)(-) has been detected at 1077 cm(-1) and 1084 cm(-1) respectively. H(3)PO(4) and D(3)PO(4) is hydrated in aqueous solution which could be verified by Raman spectroscopy following the νP[double bond, length as m-dash]O and ν(s)P(OH)(3) mode as a function of temperature. These modes show a pronounced temperature dependence inasmuch as νP[double bond, length as m-dash]O shifts to higher wavenumbers with temperature increase and ν(s)P(OH)(3) to lower wavenumbers. In the range between 300-600 cm(-1) the deformation modes have been observed. In very dilute H(3)PO(4) solutions however, the dissociation product is the dominant species. The dissociation degree, α for H(3)PO(4)(aq) and D(3)PO(4)(D(2)O) as a function of dilution has been measured at 23 °C. In these dilute H(3)PO(4)(aq) and D(3)PO(4)(D(2)O) solutions no spectroscopic features for a dimeric species of the formula H(6)P(2)O(8) and D(6)P(2)O(8) could be detected. Quantitative Raman measurements have been carried out to follow the dissociation of H(3)PO(4) and D(3)PO(4) over a very broad concentration range and also as a function of temperature. From the dissociation data, the pK(1) value for H(3)PO(4) has been determined to 2.14(1) and for D(3)PO(4) to 2.42(1) at 23 °C. In the temperature interval from 24.5 to 99.7 °C the pK(1) values for H(3)PO(4)(aq) have been determined and thermodynamic data have been derived.
在 23°C 下，对水和重水中的磷酸进行了研究，浓度范围很宽（0.00873-1.560 mol kg(-1))，使用拉曼和红外光谱法进行了研究。H(3)PO(4)(aq)和 D(3)PO(4)(D(2)O)中 PO(4)骨架（C(3v)对称）的振动模式已被分配。除了 P-O 伸缩模式外，还检测到了一个变形模式，分别为 1250 和 935 cm(-1)处的 δPO-H(D)。除了磷酸和重磷酸的模式外，还检测到了离解产物 H(2)PO(4)(-)和 D(2)PO(4)(-)的模式，分别为 1077 cm(-1)和 1084 cm(-1)。H(3)PO(4)和 D(3)PO(4)在水溶液中是水合的，这可以通过拉曼光谱法根据 νP[双键，长度为 m-dash]O 和 ν(s)P(OH)(3)模式随温度的变化来验证。这些模式显示出明显的温度依赖性，因为 νP[双键，长度为 m-dash]O 随着温度的升高向较高的波数移动，而 ν(s)P(OH)(3)向较低的波数移动。在 300-600 cm(-1)范围内观察到了变形模式。然而，在非常稀的 H(3)PO(4)溶液中，离解产物是主要物质。在 23°C 下，测量了 H(3)PO(4)(aq)和 D(3)PO(4)(D(2)O)的离解度α随稀释的变化。在这些稀 H(3)PO(4)(aq)和 D(3)PO(4)(D(2)O)溶液中，没有检测到 H(6)P(2)O(8)和 D(6)P(2)O(8)的二聚体形式的光谱特征。进行了定量拉曼测量，以在非常宽的浓度范围内并随温度变化来跟踪 H(3)PO(4)和 D(3)PO(4)的离解。根据离解数据，确定了 H(3)PO(4)的 pK(1)值为 2.14(1)，D(3)PO(4)的 pK(1)值为 2.42(1)，温度为 23°C。在 24.5 至 99.7°C 的温度范围内，确定了 H(3)PO(4)(aq)的 pK(1)值，并得出了热力学数据。
