Figure  shows a projection of tungsten bronze structure crystal in the (001) surface. When the six position A1, A2 are not all filled by cation and positions C is completely empty, called as non-full structure (such as SBN, CSBN etc.); when the six position A1, A2 are all filled with cations and position C is completely empty, called full structure (such as barium sodium niobate BNN, etc.); when the six position of A1, A2 and four positions of C are filled by cation, called completely full structure. Full or completely full type of TB structure has excellent optical stability. Experiments show that the full structure TB will not appear at room temperature (or less serious), "light damage"; however, the non-full structure crystal of TB is sensitive to "light damage".

 

The full structure crystal of TB is very important in laser applications, a large number of full  structure of TB compound showed up in recent years (or completely full type) is developed on this basis. During the preparation of these compounds crystal, in order to meet the neutral and completely fill the six positions A, different divalent cations are often introduced to fill position A (such as Li ⁺, Na ⁺, Bi^{3 +} and other rare earth elements), other available ions (such as Zr^{4 +}, Ti^{4 +}, Ws^{8 +}, etc.) can be used in replacement of Nb^{5 +} ions.

 

For niobate with non-full TB structure , it can further improved its crystalline materials quality or changing their various properties through molecular design and doping. In addition, niobate with TB structure most has excellent ferroelectric properties. The differences in their structure and synthetic ingredients have a significant impact on its ferroelectric properties and other properties (obvious examples is SBN) Therefore, to obtain crystalline materials with the desired properties, studies on such materials composition of doping and solid solution are of great significance. There are few mechanism study on niobate with TB basin structure ferroelectric phenomenon, now that they are considered as "one-dimensional type" ferroelectrics, of which the motor iron mechanism can be explained by the view of ion displacement polarization: when the crystal was cooled to curie point below, all the metal ions in octahedral centers and Al, A2 position displaced with respect to the vicinity oxygen atoms plane, resulting in the generation of spontaneous polarization of the crystal.