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首页> 外文期刊>European Journal of Glass Science and Technology, PartB. Physics and Chemistry of Glasses >The effect of monovalent and divalent metal oxides on the network cohesion of binary phosphate glasses: aspects revealed by spectral determination of basicity trends
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The effect of monovalent and divalent metal oxides on the network cohesion of binary phosphate glasses: aspects revealed by spectral determination of basicity trends

机译：一价和二价金属氧化物对二元磷酸盐玻璃网络内聚力的影响：通过碱度趋势的光谱测定揭示的方面

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The electron-donor ability of the O~(δ-) anions has a significant influence on the chemical bonding pattern in phosphate glasses. The variation in O~(δ-) electron-donor ability with composition can be qualitatively estimated by monitoring the evolution of the equilibria between the oxidation states of a transition metal dopant. We report the use of optical spectroscopy to examine the equilibria between the oxidation states of dopants like Cu, Mo, or Ti,for the case of R~(m+)0-P2O5 (m=l or 2) type glassy hosts (melted under reductive conditions). It was determined that the presence of an R~(2_)0 metal oxide increases the stability of the lower dopant oxidation states (Cu°, Cu~+ Mo~(3+), Ti~(3+)), while the presence of a R~(1+)0 oxide favours the higher oxidation states (Cu~(2+),Mo~(5+), Ti~(4+)). It follows that, while O~(δ-) donor ability is increased by R~(1+)O oxides, it is reduced by R~(2+)O. A possible explanation for this finding is that small R~(2+) type cations form strong coordinative bonds with O~(δ-),from different phosphate layers or chains, leading to overall enhancement of network cohesion despite the depolymerisation they also cause. The R~(1+) cations establish predominantly ionic inter-layer bonds, weaker than the broken-P-O-P-bonds; this leads to a less compact network. Such a model is consistent with the observed effect on phosphate glass properties of, respectively, R~(1+)O and R~(2+)I oxides.
机译：O〜（δ-）阴离子的电子给体能力对磷酸盐玻璃中的化学键模式有重要影响。 O〜（δ-）电子给体能力随组成的变化可以通过监测过渡金属掺杂剂氧化态之间平衡的演变来定性地估计。对于R〜（m +）0-P2O5（m = l或2）型玻璃态主体（在还原条件）。可以确定的是，R〜（2_）0金属氧化物的存在增加了较低掺杂剂氧化态（Cu°，Cu〜+ Mo〜（3 +），Ti〜（3+））的稳定性。 R〜（1+）0的氧化物的较高的氧化态（Cu〜（2 +），Mo〜（5 +），Ti〜（4+））有利。由此可见，尽管R〜（1+）O氧化物提高了O〜（δ-）供体能力，但R〜（2+）O却降低了供体能力。这一发现的可能解释是，小的R〜（2+）型阳离子与O〜（δ-）形成了来自不同磷酸盐层或链的强配位键，尽管它们也引起了解聚，但导致网络内聚力的整体增强。 R〜（1+）阳离子主要建立离子层间键，比断裂的P-O-P键弱。这导致网络的紧凑性降低。这样的模型与观察到的分别对R〜（1+）O和R〜（2+）I氧化物的磷酸盐玻璃性能的影响是一致的。

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