Introduction to Inorganic Chemistry
This is primarily the science of water and substances dissolved in water. To
understand inorganic chemistry, we must first take a moment to discuss the nature of water.
Water (H2O) is an incredible substance. It is very stable, and is able to dissolve a
wide variety of other useful materials and carry them, in suspension, wherever it goes. In
addition, it possesses an electrical ‘charge’: one side is positive, the other negative, like a
magnet. This property is known as polarity, and makes water a polar substance (because of
the two poles). This positive-negative interrelation allows water to hold together very well,
as well as dissolve many things that have an electrical charge to them (and is also the reason
why you shouldn’t keep a radio next to the full bathtub). Finally, water has yet another
remarkable property: hydrogen bonding. Although this topic will be discussed in more detail
later on, suffice it to say that it is the reason behind why ice is lighter than water: when
liquid, water molecules are attracted to each other by the hydrogen bonds which pack them
together very densely; when frozen, the water molecules crystallize and the hydrogen bonds
disappear, giving rise to ice, which is less dense and (thankfully!) floats on water rather than
sinking. Imagine if, every winter, lakes and ponds turned into solid ice!
Normally, water doesn’t exist alone. Even the purest spring water will have
uncountable amounts of solutes, or dissolved substances, present within it. For the purposes
of our discussion on inorganic chemistry, most of these solutes will be salts: from common
table salt, or sodium chloride, to calcium carbonate (limestone), magnesium chloride,
potassium sulfate, and a host of other salts leached from the bedrock and soil. You will
notice that each of these substances is identified by a two-part name: in the case of table salt,
for example, we have the sodium and the chloride. Each of these parts is termed an ion, which
is why this branch of chemistry is often called ionic chemistry. An ion is basically just an atom
that has an electrical charge on it, either positive or negative; you can begin to see, then,
why water is so good at dissolving salts: the positive ions stick to the negative side of water,
and the negative ions stick to the positive side. In their natural states (not dissolved in water,
that is), salts consist of a positive and a negative ion attached to each other due to electrical
attraction. Getting back to table salt, we have the positive sodium ion stuck to the negative
chloride ion. When table salt comes into contact with water, it is broken in half, with each
of its ions sticking to the appropriate side of the water molecule.
Ions are extremely important to life on earth. Primarily, since they have an electrical
charge, they are essential in transmitting the subtle electrical currents that travel constantly
throughout any living being. For example, our hearts are regulated by a delicate balance of
sodium ions and potassium ions, and the interaction of these two allow the heart muscle to
beat. Nervous impulses, which are basically small electric shocks, are transmitted along the
nerves by a chain of sodium and calcium ions. Our blood relies on the hemoglobin
molecule, at the center of which sits a positive iron ion just waiting to grab onto a negative
oxide ion (the ion oxygen forms) to ferry it around the bloodstream. Without ions, life as
we know it could not exist. Without water, ions couldn’t ever break free from the salt
matrix in which they are normally locked.
Even water can’t hold an infinity of ions, however. There comes a point when there
are just too few water molecules left to break the ionic salts up. This is termed saturation,
and is a concept we will encounter often in crafting herbal extracts: it simply defines the
point at which water can no longer dissolve any more salt, and any extra will fall to the
bottom of the container and become unavailable (a process called precipitation). There are
ways to remedy this situation: the simplest is just to add more water and stir in the
precipitated salt. Another is to increase the temperature of the water: the warmer it gets,
the more ions it can hold.