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 <para id="fs-idp17717312">A series of six elements called the metalloids separate the metals from the nonmetals in the periodic table. The metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. These elements look metallic; however, they do not conduct electricity as well as metals so they are semiconductors. They are semiconductors because their electrons are more tightly bound to their nuclei than are those of metallic conductors. Their chemical behavior falls between that of metals and nonmetals. For example, the pure metalloids form covalent crystals like the nonmetals, but like the metals, they generally do not form monatomic anions. This intermediate behavior is in part due to their intermediate electronegativity values. In this section, we will briefly discuss the chemical behavior of metalloids and deal with two of these elements—boron and silicon—in more detail.</para>
-<para id="fs-idp189496896">The metalloid boron exhibits many similarities to its neighbor carbon and its diagonal neighbor silicon. All three elements form covalent compounds. However, boron has one distinct difference in that its 2<emphasis effect="italics">s</emphasis><sup>2</sup>2<emphasis effect="italics">p</emphasis><sup>1</sup> outer electron structure gives it one less valence electron than it has valence orbitals. Although boron exhibits an oxidation state of 3+ in most of its stable compounds, this electron deficiency provides boron with the ability to form other, sometimes fractional, oxidation states, which occur, for example, in the boron hydrides.</para>
-<para id="fs-idp63064256">Silicon has the valence shell electron configuration 3<emphasis effect="italics">s</emphasis><sup>2</sup>3<emphasis effect="italics">p</emphasis><sup>2</sup>, and it commonly forms tetrahedral structures in which it is <emphasis effect="italics">sp</emphasis><sup>3</sup> hybridized with a formal oxidation state of 4+. The major differences between the chemistry of carbon and silicon result from the relative strength of the carbon-carbon bond, carbon’s ability to form stable bonds to itself, and the presence of the empty 3<emphasis effect="italics">d</emphasis> valence-shell orbitals in silicon. Silicon’s empty <emphasis effect="italics">d</emphasis> orbitals and boron’s empty <emphasis effect="italics">p</emphasis> orbital enable tetrahedral silicon compounds and trigonal planar boron compounds to act as Lewis acids. Carbon, on the other hand, has no available valence shell orbitals; tetrahedral carbon compounds cannot act as Lewis acids. Germanium is very similar to silicon in its chemical behavior.</para>
-<para id="fs-idp125396304">Arsenic and antimony generally form compounds in which an oxidation state of 3+ or 5+ is exhibited; however, arsenic can form arsenides with an oxidation state of 3−. These elements tarnish only slightly in dry air but readily oxidize when warmed.</para>
-<para id="fs-idp421952">Tellurium combines directly with most elements. The most stable tellurium compounds are the tellurides—salts of Te<sup>2−</sup> formed with active metals and lanthanides—and compounds with oxygen, fluorine, and chlorine, in which tellurium normally exhibits an oxidation state 2+ or 4+. Although tellurium(VI) compounds are known (for example, TeF<sub>6</sub>), there is a marked resistance to oxidation to this maximum group oxidation state.</para>
+<para id="fs-idp189496896">The metalloid boron exhibits many similarities to its neighbor carbon and its diagonal neighbor silicon. All three elements form covalent compounds. However, boron has one distinct difference in that its 2<emphasis effect="italics">s</emphasis><sup>2</sup>2<emphasis effect="italics">p</emphasis><sup>1</sup> outer electron structure gives it one less valence electron than it has valence orbitals. Although boron exhibits an oxidation state of +3 in most of its stable compounds, this electron deficiency provides boron with the ability to form other, sometimes fractional, oxidation states, which occur, for example, in the boron hydrides.</para>
+<para id="fs-idp63064256">Silicon has the valence shell electron configuration 3<emphasis effect="italics">s</emphasis><sup>2</sup>3<emphasis effect="italics">p</emphasis><sup>2</sup>, and it commonly forms tetrahedral structures in which it is <emphasis effect="italics">sp</emphasis><sup>3</sup> hybridized with a formal oxidation state of +4. The major differences between the chemistry of carbon and silicon result from the relative strength of the carbon-carbon bond, carbon’s ability to form stable bonds to itself, and the presence of the empty 3<emphasis effect="italics">d</emphasis> valence-shell orbitals in silicon. Silicon’s empty <emphasis effect="italics">d</emphasis> orbitals and boron’s empty <emphasis effect="italics">p</emphasis> orbital enable tetrahedral silicon compounds and trigonal planar boron compounds to act as Lewis acids. Carbon, on the other hand, has no available valence shell orbitals; tetrahedral carbon compounds cannot act as Lewis acids. Germanium is very similar to silicon in its chemical behavior.</para>
+<para id="fs-idp125396304">Arsenic and antimony generally form compounds in which an oxidation state of +3 or +5 is exhibited; however, arsenic can form arsenides with an oxidation state of –3. These elements tarnish only slightly in dry air but readily oxidize when warmed.  Antimony reacts readily with stoichiometric amounts of fluorine, chlorine, bromine, or iodine, yielding trihalides or, with excess fluorine or chlorine, forming the pentahalides SbF<sub>5</sub> and SbCl<sub>5</sub>. Depending on the stoichiometry, it forms antimony(III) sulfide, Sb<sub>2</sub>S<sub>3</sub>, or antimony(V) sulfide, Sb<sub>2</sub>S<sub>5</sub>, when heated with sulfur. As expected, the metallic nature of the element is greater than that of arsenic, which lies immediately above it in group 15.</para>
+<para id="fs-idp421952">Tellurium combines directly with most elements. The most stable tellurium compounds are the tellurides—salts of Te<sup>2−</sup> formed with active metals and lanthanides—and compounds with oxygen, fluorine, and chlorine, in which tellurium normally exhibits an oxidation state +2 or +4. Although tellurium(VI) compounds are known (for example, TeF<sub>6</sub>), there is a marked resistance to oxidation to this maximum group oxidation state.</para>
 <section id="fs-idp249805056">
 <title>Structures of the Metalloids</title>
 <para id="fs-idm34751888">Covalent bonding is the key to the crystal structures of the metalloids. In this regard, these elements resemble nonmetals in their behavior.</para>