Complex sleep apnea is the term used to describe a form of sleep disordered breathing in which repeated central apneas (>5/hour) persist or emerge when obstructive events are extinguished with positive airway pressure (PAP) and for which there is not a clear cause for the central apneas such as narcotics or systolic heart failure.
Giant covalent structures. Such as silicon dioxide, have extremely high melting points and low solubility in all solvents. They are non-volatile and conductivity depends on the availability of electrons in the valence shell (eg graphite). If all electrons are used in bonding they are insulators.ow melting points:- The bonds between molecules are very weak, especially when the molecules are small. It only requires a small quantity of heat energy to create enough molecular vibration to break the molecules attraction for one another and the solid melts.
Here is a short list of the main properties of covalent compounds: Most covalent compounds have relatively low melting points and boiling points. Covalent compounds usually have lower enthalpies of fusion and vaporization than ionic compounds. Covalent compounds tend to be more flammable than ionic compounds. When dissolved in water, they don't conduct electricity. Maybe you'll be interested in comparison of properties of ionic and covalent compound so here is a link where you can learn it. Deevona Â· Â· 2 comments Â· Oct 2 2014.