Structures and Similarities to Ice

because all three common hydrate structures consist of about 85% water on a molecular basis, many of the hydrate mechanical properties resemble those of ice Ih. Among the exceptions to this heuristic are yield strength, thermal expansivity, and thermal conductivity. The final portion of this chapter examines mechanical, electrical, and transport properties with emphasis on those properties that differ from ice. 

Less common clathrate hydrates formed by compounds other than natural gas guests (such as Jeffrey s structures III-VII, structure T, complex layer structures) and high pressure hydrate phases are also briefly described to provide a comprehensive account of clathrate hydrate structural properties. 

The purpose of this chapter is also to provide the reader with a source of reference of the structural properties of hydrates. A summary of the key tabulated data given in this chapter is as follows  

This chapter focuses on the question, What are hydrates and Chapter 3 concerns the question, How do hydrates form Although a few thermodynamic properties are discussed in this chapter, the phase equilibrium conditions are considered in Chapters 4, 5, and 6. 

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