Comments on paper "Lebedev's experiment and crystallite glass models."

In a recent paper [1], Arrieta raised questions about the nanoflake model, proposed by Cheng approximately 9 years ago [2]. Arrieta noted that the model for the structure of silica glass has already been critiqued and believes it relies on a large amount of 180° Si-O-Si bond angles, which are inconsistent with available experimental results. Because the structural model is incorrect, the explanation of the microscopic origin of the endothermic peak in Lebedev's experiment on borosilicate crown glass presented in the article titled "Revisiting Lebedev's one-century-old experiment" [3] should be considered invalid. It is true that shortly after the nanoflake model was proposed, Professor A. C. Wright published two letters criticizing the model [4,5]. The major problem in the letters concerns the 180˚ Si-O-Si bond angle, as Arrieta indicated [1]. Figure 1 shows an asymmetrical unimodal profile, ranging from 120˚ to 180˚ with the maximum at 144˚, obtained by Mozzi & Warren [6]. This wide variation of the Si-O-Si bond angle shows the distinction between the vitreous and crystalline forms of silica. It is essential to use Figure 1 to check the nanoflake model.