REPORT
LAB WORK OF SCIENCE PRACTICE 1
MOLECULE SHAPE
Arranged By:
Novia Anggraeni
(103152440021)
International science education
PRODI PENDIDIKAN IPA
FAKULTAS MATEMATIKA DAN ILMU PENGETAHUAN ALAM
UNIVERSITAS NEGERI YOGYAKARTA
2011
A. OBJECTIVE
1. Students are able to make design the molecule shape
2. Students are able to measurement of length, diameter and angle to design a
molecule shape.
B. BACK GROUND
Molecules are made up of two or more atoms, either of the same element or
of two or more different elements, joined by one or more covalent chemical
bonds. According to the kinetic-molecular theory, the molecules of a substance
are in constant motion. The state (solid, liquid, or gaseous) in which matter
appears depends on the speed and separation of the molecules in the matter.
Substances differ according to the structure and composition of their molecules. A
molecular compound is represented by its molecular formula; for example, water
is represented by the formula H2O. A more complex structural formula is
sometimes used to show the arrangement of atoms in the molecule.
Differ in size and molecular weight as well as in structure. In a chemical
reaction between molecular substances, the molecules are often broken apart into
atoms or radicals that recombine to form other molecules, i.e., other substances.
In other cases two or more molecules will combine to form a single larger
molecule, or a large molecule will be broken up into several smaller molecules.
Molecules can assume many shapes and sizes. Molecules of hydrogen gas,
H2, are very small; each consists of two atoms of hydrogen. Water molecules,
H2O, are much larger, containing an atom of oxygen as well as two of hydrogen.
The atoms in a water molecule are arranged at the corners of an isosceles triangle;
the oxygen atom is located where the two equal sides meet and the angle between
these sides is about 105°. A carbon dioxide molecule, CO2, is linear, with the two
oxygen atoms an equal distance on either side of the carbon atom. In methane,
CH4, the hydrogen atoms are arranged at the corners of a tetrahedron with the
carbon atom in the center. In benzene, C6H6, the carbon atoms form a hexagonal
ring with a hydrogen atom joined to each carbon atom. More complex molecules
resemble rings, chains, helices, or other forms.
C. BASIC THEORY
Methane is the simplest hydrocarbon is a gas with chemical formula CH4.
Pure methane is odorless, but if used for commercial purposes, is usually added
little sulfur smell to detect leaks that may occur. As the main component of
natural gas, methane is the primary fuel source. Combustion of one molecule of
methane with oxygen will release one molecule of CO2 (carbon dioxide) and
two molecules of H2O (water):
CH4 + 2O2 → CO2 + 2H2O
Methane is a chemical compound with the chemical formula CH 4 . It is the
simplest alkane , the principal component of natural gas , and probably the most
abundant organic compound on earth. The relative abundance of methane makes
it an attractive fuel. Because, however it is a gas at normal conditions , methane
is difficult to transport from its source. Methane is a relatively potent greenhouse
gas. The concentration of methane in the Earth's atmosphere in 1998, expressed
as a mole fraction , was 1745 nmol/mol (parts per billion, ppb), up from 700
nmol/mol in 1750. By 2008, however, global methane levels, which had stayed
mostly flat since 1998, had risen to 1,800 nmol/mol.
Methane, CH 4
The simple view of the bonding in methane
You will be familiar with drawing methane using dots
and crosses diagrams, but it is worth looking at its
structure a bit more closely.
There is a serious mis-match between this structure and
the modern electronic structure of carbon, 1s 2 2s 2 2p x 1
2p
y
1
The modern structure shows that there are only 2 unpaired electrons for
hydrogens to share with, instead of the 4 which the
simple view requires.
You can see this more readily using the electrons-inboxes notation. Hanya 2-tingkat elektron yang akan
ditampilkan. Only the 2-level electrons are shown. The 1s
2
electrons are too
deep inside the atom to be involved in bonding. The only electrons directly
available for sharing are the 2p electronsWhy then isn't methane CH 2 ?
Promosi elektron Promotion of an electron
When bonds are formed, energy is released and the
system becomes more stable If carbon forms 4 bonds
rather than 2, twice as much energy is released and so
the resulting molecule becomes even more stable.
There is only a small energy gap between the 2s and 2p
orbitals, and so it pays the carbon to provide a small
amount of energy to promote an electron from the 2s to
the empty 2p to give 4 unpaired electrons. The extra
energy released when the bonds form more than
compensates for the initial input.
The carbon atom is now said to be in an excited state .
Note: People sometimes worry that the promoted electron is drawn as an uparrow, whereas it started as a down-arrow. The reason for this is actually fairly
complicated - well beyond the level we are working at. Just get in the habit of
writing it like this because it makes the diagrams look tidy.
Now that we've got 4 unpaired electrons ready for bonding, another problem
arises. In methane all the carbon-hydrogen bonds are identical, but our electrons
are in two different kinds of orbitals. You aren't going to get four identical bonds
unless you start from four identical orbitals.
Hibridisasi Hybridisation
The electrons rearrange themselves again in a process
called hybridisation. This reorganises the electrons into
four identical hybrid orbitals called sp
3
hybrids
(because they are made from one s orbital and three p
orbitals). You should read "sp 3 " as "sp three" - not as "sp cubed".
sp
3
hybrid orbitals look a bit like half ap orbital, and they
arrange themselves in space so that they are as far apart as
possible.You can picture the nucleus as being at the centre
of a tetrahedron (a triangularly based pyramid) with the
orbitals pointing to the corners. For clarity, the nucleus is drawn far larger than it
really is.
What happens when the bonds are formed?
Remember that hydrogen's electron is in a 1s orbital - a spherically symmetric
region of space surrounding the nucleus where there is some fixed chance (say
95%) of finding the electron. When a covalent bond is formed, the atomic
orbitals (the orbitals in the individual atoms) merge to produce a new molecular
orbital which contains the electron pair which creates the bond.
Four molecular orbitals are formed, looking rather like the original sp 3 hybrids,
but with a hydrogen nucleus embedded in each lobeEach orbital holds the 2
electrons that we've previously drawn as a dot and a cross.
The principles involved - promotion of electrons if necessary, then hybridisation,
followed by the formation of molecular orbitals - can be applied to any
covalently-bound molecule.
The shape of methane
When sp
3
orbitals are formed, they arrange themselves so that they are as far
apart as possible. That is a tetrahedral arrangement, with an angle of 109.5°.
Nothing changes in terms of the shape when the hydrogen atoms combine with
the carbon, and so the methane molecule is also tetrahedral with 109.5° bond
angles.
Water is a chemical substance with chemical formula H2O: one molecule
of water is composed of two hydrogen atoms covalently bonded to one oxygen
atom. Water is colorless, tasteless and odorless at standard conditions, at a
pressure of 100 kPa (1 bar) and temperature of 273.15 K (0°C). This chemical is
an important solvent, which has the ability to dissolve many other substances,
such as salts, sugars, acids, several types of gases and many kinds of organic
molecules.
The reason why hydrogen bonded with oxygen to form liquid phase
condition, is because oxygen is more electronegative than the other elements
(except fluorine). Oxygen atoms pull on the electron-electron bond is much
stronger than those carried by hydrogen atoms, leaving the number of positive
charges on both hydrogen atoms, and the amount of negative charge on the
oxygen atom. The existence of a charge on each atom is made of water
molecules have a number of dipole moment. Electric force of attraction between
water molecules due to dipole makes each of the molecules close together,
making it difficult to be separated and that ultimately raise the boiling point of
water. Force of attraction is called hydrogen bonding.
Water is often referred to as the universal solvent because water dissolves
many chemicals. Water is in dynamic equilibrium between liquid and solid
phases under standard pressure and temperature. In the form of ions, water can
be described as a hydrogen ion (H+) that associate (bind) with a hydroxide ion
(OH-).
Water molecules can be broken down into elements stream home with
electric current. This process is called electrolysis of water. At the cathode, two
water molecules react with the capture of two electrons, is reduced to H2 gas and
hidroxcide ions (OH-). Meanwhile at the anode, two other water molecules break
down into oxygen gas (O2), release 4 H+ ions and electrons flowing into the
cathode. H+ and OH- have re-neutralization, forming several water molecules.
Equivalent overall reaction of water electrolysis can be written as follows.
Hydrogen and oxygen gas produced from this reaction to form bubbles on
the electrodes and can be collected. This principle is then used to produce
hydrogen and hydrogen peroxide (H2O2) which can be used as fuel for hydrogen
vehicles. In the form of molecules known as the valence bond theory. This
theory states that the bond between atoms occurs by way of mutual overlap of
atomic orbitals. Electrons in overlapping orbitals must have opposite spin
quantum numbers.
Compress
between the two sub's skin is not strong, because of the
spherical charge distribution, and therefore generally bond s - s is relatively
weak. Sub skin "p" can bertindih with sub skin "s" or sub-skin "p" other,
relatively strong bond, this is because the sub-skin "p" is concentrated in a
particular direction.
Molekul H2O: - konfigurasi atom H : 1s1
-
konfigurasi atom O : 1s2 2s2 2Px2 2py1 2pz1
In the O atoms have 2 electrons in an unpaired state (2py and 2pz orbitals), each
of these orbitals will overlap with the 1s orbitals of two atoms of H. Position p
orbitals perpendicular, expected bond angle of 90o, but because of the influence
of electron pairs 2px, then the bond will be rejected and the shape of 104.5o.
BEBERAPA BENTUK GEOMETRI IKATAN, ANTARA LAIN :
Jenis ikatan
Jumlah
ikatan
Bentuk
maksimum
geometrik
sp
2
Linier
sp2
3
Segitiga datar
sp3
4
Tetrahedron
dsp3
5
sp2d ; dsp2
4
Segiempat datar
d2sp3 ; sp3d2
6
Oktahedron
Formulate Type Molecules
Trigonal
bipiramid
This type of molecule is a notation that states the number of pairs of electrons
around the central atom of a molecule, either free electrons or electron bond.
Types of molecules is determined in the following manner: Atom center
expressed with the symbol A. These atoms represent atoms that bind several
atoms entrants. Each pair of bonding electrons is given by X. Each pair of free
electrons is given by E.
Example: IF3 molecule consisting of three electron pairs and 2 lone tie
formulated as AX3E2
This type of molecule can be determined with the following steps:
1. Binds Single Binary Compounds
If the central atom is only a single bond, each bond using only one
electron from the atom center. Thus, the number of lone pairs (E) in accordance
with the following formula:
EV = the number of valence electrons the central atom
X = the number of bonding electron pairs
E = the number of lone pairs
Thus, the type of molecule can be determined in the following order:
1. Determine the number of valence electrons the central atom (EV)
2. Determine the number of bonding electron pairs (X)
3. Determine the number of lone pairs
Example:
Determining the type of water molecule (H2O)
The number of valence electrons the central atom (oxygen) = 6
The number of bonding electron pairs (X) = 2
The number of lone pairs (E) = (6-2): 2 = 2
2. Binary Compounds Covalently Binds Association Duplicate or Coordinates.
If the central atom to form a double bond or coordinate covalent bonds,
each bond will use the two valence electrons from the atom center.
Water, H2O
Following the same logic as before, you'll find that the oxygen has four
pairs of electrons, two of which are lone pairs. Water also will take a tetrahedral
arrangement. Currently narrower bond angles of 104 °, because the repulsion of
two lone pairs. The form cannot be described with tetrahedral, because we just
saw? oxygen and hydrogen? not the lone pairs. Water bend or shape is described
by V.
D. TOOLS AND MATERIA
1. Wire
2. Ping pong balls
3. Wax
4. Pliers
5. Arc
6. clay
E. PROCEDURE
Creating a model of H2O
1. Prepare tools and materials
2. Heat the wire, then wire was thrust to the ping pong ball
3. Measuring the length of wire to match with the distance between central atom.
4. Heating wire on the other end and was thrust into a big ball
5. Measuring the degree of atoms of 104.5 º H and repeat steps 2-4
Creating a model of methane (CH4)
1. Prepare tools and materials
2. Heating the wire, then thrust of wire to the ping pong ball
3. Measuring the length of wire to match with the distance between central atom.
4. Heating wire on the other end and was thrust into a big ball
5. Measuring the degree of atoms of 109.5 º H and repeat steps 2-5
6. For of the other H bonds
F. OBSERVATION RESULT
G. DISCUSSION
Pada percobaan yang praktikan lakukan pada hari kamis, 27 Oktober 2011
yang berada pada Laboratorium IPA 2, praktikan melakukan percobaan tentang
“Bentuk Molekul”. Dalam bentuk molekul ini praktikan melakukan percobaan
dengan model molekul yaitu metana (CH4) dan air (H2O). Metana (CH4) adalah
gas, tidak berbau tidak berwarna yang mudah terbakar. Hal ini digunakan
terutama sebagai bahan bakar untuk membuat panas dan cahaya. Hal ini juga
digunakan untuk memproduksi bahan kimia organik. Metana dapat dibentuk oleh
pembusukan bahan-bahan alami dan umum di tempat pembuangan sampah, rawarawa, sistem septik dan selokan. Sedangkan air (H2O) adalah substansi kimia
dengan rumus kimia H2O: satu molekul air tersusun atas dua atom hidrogen yang
terikat secara kovalen pada satu atom oksigen. Air bersifat tidak berwarna, tidak
berasa dan tidak berbau pada kondisi standar, yaitu pada tekanan 100 kPa (1 bar)
and temperatur 273,15 K (0 °C). Zat kimia ini merupakan suatu pelarut yang
penting, yang memiliki kemampuan untuk melarutkan banyak zat kimia lainnya,
seperti garam-garam, gula, asam, beberapa jenis gas dan banyak macam molekul
organik.
Adapun dalam percobaan kali ini praktikan menggunakan bentuk molekul
CH4 dan H2O karena dari kedua molekul tersebut mempunyai bentuk molekul
yang berbeda dari perkiraan awam bentuk molekul yang sebenarnya. Bentuk
molekul tersebut dipengaruhi oleh beberapa faktor yang akan dibahas nanti.
Bentuk molekul itu sendiri menggambarkan kedudukan atom-atom di dalam suatu
molekul, yaitu kedudukan atom-atom dalam ruang tiga dimensi dan besarnya
sudut-sudut ikatan yang dibentuk dalam suatu molekul, serta ikatan yang terjadi
pada molekul tersebut yang dibentuk oleh pasangan-pasangan elektron.
Dalam percobaan kali ini mempunyai tujuan agar praktikan dapat membuat
design dari model molekul dan juga agar praktikan dapat mengukur panjang,
diameter, dan sudut dari design percobaan bentuk molekul tersebut. Untuk
menjawab tujuan yang pertama maka praktikan membuat design percobaan sesuai
dengan keatifitas masing-masing. Langkah-langkah yang harus dilakukan untuk
membuat model bentuk molekul dari metana dan air yaitu untuk membuat model
H2O yang pertama kali dilakukan adalah menyiapkan alat dan bahan seperti wire,
ping pong balls, wax, pliers, arc, clay. Setelah itu memanaskan kawat, kemudian
menusukan kawat ke bola ping pong hal itu dilakukan sampai kawat tersebut
dapat masuk ke dalam bola pim pong itu. Kemudian mengukur pajang kawat agar
sesuai dengan jarak atar pusat atom. Kami mengukur untuk panjang tangan air 9.6
cm, diameter O 6 cm, dan diameter H 3,5 cm. Setelah itu memanaskan kawat
ujung yang lain dan menusukannya ke bola besar dan langkah yang terakhir
adalah mengukur derajat atar atom sebesar 104,5º H dan mengulangi langkah 2-4
untuk atom H yang lain. Semenrata itu untuk membuat model molekul metana
hampir sama yaitu menyiapkan alat dan bahan seperti pada air, kemudian
memanaskan kawat, kemudian menusukan kawat ke bola ping pong setelah itu
mengukur pajang kawat agar sesuai dengan jarak atar pusat atom. Dalam metana
panjang tangan air 10,9 cm, diameter 7 cm, dan diameter H 3,5 cm. langkah
selanjutnya memanaskan kawat ujung yang lain dan menusukannya ke bola besar
langkah terakhir yaitu mengukur derajat atar atom sebesar 109,5º H dan
mengulangi langkah 2-5 untuk ikatan H yang lain.
Struktur molekul metana (CH4) atom pusatnya mempunyai 4 lengan dengan
membentuk sudut antar lengan adalah sebesar 109,50. Jadi sudut C-H-C sebesar
109,50. Terbentuknya sudut antar lengan dapat dijelaskan bahwa dalam senyawa
karbon (C) yang mempunyai nomer atom 6, strukturnya dijelaskan dengan
mengasumsikan empat orbital sp3 ekuivalen terbentuk dari satu orbital 2s dan tiga
orbital 2p. Atom karbon (C) memiliki empat elektron valensi, dan konfigurasi
elektronnya adalah 1s22s22p2, dan untuk membentuk atom tetravalen, konfigurasi
elektronnya harus berubah menjadi (1s22s2px2py2pz). Dengan hibridisasi, empat
orbital hibrida sp3 yang ekuivalen akan terbentuk. Sudut ikatan yang dibuat oleh
dua orbital hibrida sp3 adalah 109,5° (sudut tetrahedral). Inilah alasan mengapa
metana berstruktur tetrahedral. Proses hibrisdisasi yang terjadi pada CH4 adalah
sebagai berikut:
Atom C dengan nomor atom 6 mempunyai konfigurasi elektron ; 1s2 2s2 2p4
dan diagram elektron valensi :
Untuk membentuk molekul CH4, keempat elektron valensi atom karbon
harus membentuk pasangan elektron dengan elektron-elektron dari keempat atom
hidrogen yang diikatnya. Karena sudah berpasangan, elektron pada orbital 2s
tidak mungkin digunakan untuk berpasangan dengan elektron atom hidrogen.
Oleh karena itu, sebuah elektron dari orbital 2s tersebut harus dipromosikan ke
orbital 2p.
Dengan dipromosikannya, masing-masing elektron akan membentuk
pasangan elektron bersama dengan 4 elektron dari keempat atom hidrogen. Bila
ditinjau secara teoritis, tingkat energi keempat pasangan-pasangan elektron
tidaklah sama. Namun dalam pengamatan spektrum menunjukkan bahwa keempat
ikatan pada CH4 adalah identik. Ini berarti tingkat energi keempat pasang elektron
tersebut setingkat. Oleh karena itu, dapat disimpulkan bahwa orbital yang terjadi
pada ikatan CH4 terbentuk dari sebuah atom s dan tiga orbital p membentuk
orbital sp3 yang tingkat energinya sama. Selanjutnya orbital hibrida yang belum
berpasangan ini, akan berpasangan dengan elektron–elektron dari keempat atom
H yang berada di orbital sp3. Tetrahedron adalah piramida dengan dasar segitiga.
Atom karbon terletak di tengah-tengah dan hidrogen pada empat sudutnya. Semua
sudut ikatan adalah 109.5°.
Sedangkan untuk H2O meskipun struktur elektronnya tetrahedron namun
strukturnya tidaklah sempurna, karena sudut yang dibentuk antar elektron
ikatannya adalah 104,50. Terbentuknya sudut antar lengan dapat dijelaskan bahwa
dalam senyawa oksigen (O) yang mempunyai nomer atom 8, strukturnya
dijelaskan dengan mengasumsikan empat orbital sp3 ekuivalen terbentuk dari satu
orbital 2s dan tiga orbital 2p. Atom oksigen (O) memiliki enam elektron valensi,
dan konfigurasi elektronnya adalah 1s22s22p4, dan untuk membentuk atom
tetravalen, konfigurasi elektronnya harus berubah menjadi (1s22s2px2py2pz).
Dengan memenuhi aturan aturan yang berlaku dalam pengisian konfigurasi
elekton maka akan kita ketahui dalam atom O terdapat 2 elektron dalam keadaan
yang tidak berpasangan (orbital 2py dan 2pz), masing-masing orbital ini akan
bertindihan dengan orbital 1s dari 2 atom H. Kedudukan orbital-orbital p saling
tegak lurus, diharapkan sudut ikatannya sebesar 90o, tetapi karena adanya
pengaruh pasangan elektron 2px, maka kedua ikatan tersebut akan tertolak dan
membentuk sebesar 104,5o.
Pada H2O terjadi ikatan kovalen polar karena pada H2O terdapat dua
pasangan elektron bebas. Pasangan elektron bebas menyebabkan terjadinya
perubahan sudut ikatan dan perubahan bentuk molekul. Adanya tolak menolak
antara pasangan elektron bebas dangan pasangan elektron bebas yang lain dalam
molekul air sangat besar bila dibandingkan dengan gaya tolak menolak antar
pasangan elektron ikatan pada molekul air. Hal ini menyebabkan jarak antara
atom H dengan atom H paling dekat dari atom lain. Dengan demikian bentuk
molekulnya bengkok dengan sudut ikatnya 104,50 membentuk huruf V.
104,5o
Atom-atom dalam berikatan untuk membentuk molekul melibatkan
alektron-elektron pada kulit terluar. Ikatannya terbentuk karena pemakaian
bersama pasangan elektron (ikatan kovalen). Oleh sebab itu bentuk molekul
ditentukan oleh kedudukan pasangan-pasangan elektron tersebut. Di dalam
molekul senyawa umumnya terdapat atom yang dianggap sebagai atom pusat.
Misalnya pada senyawa H2O sebagai atom pusat adalah atom oksigen. Pasangan
elektron yang berada pada di sekitar atom pusatnya dapat dibedakan menjadi
dua,yakni pasangan elektron ikatan (p.e.i) dan pasangan elektron bebas (p.e.b).
Pasangan elektron bebas mempunyai gaya tolak yang lebih besar dari pada
pasangan elektron ikatan. Hal itu terjadi karena pasangan elektron bebas hanya
terikat pada satu atom sehingga gerakannya lebih leluasa. Urutan kekuatan tolakmenolak di antara pasangan elektron adalah sebagai berikut :
Tolakan antar pasangan elektron bebas > tolakan antara pasangan elektron
bebas dengan pasangan elektron ikatan > tolakan antara pasangan elektron ikatan.
Pasangan-pasangan elektron dalam suatu molekul akan menempatkan diri,
sehingga gaya tolak-menolak pasangan elektron itu serendah mungkin. Agar
kedudukan pasangan elektron tersebut menghasilkan gaya tolak-menolak yang
paling rendah, maka pasangan elektron tersebut akan berada pada jarak yang
saling berjauhan satu sama lain.
Pada percobaan kali ini apabila dilihat dari aspek fisika, kimia dan biologi yaitu:
Fisika: yaitu pada saat pengukuran panjang tangan antar atom, dan juga pada saat
pengukuran diameter masing-masing atom dan pengukuran besarnya
sudut dari bentuk molekul masing-masing.
Kimia : rumus kimia dari molekul yang terbentuk yaitu:
CH4 + 2O2 → CO2 + 2H2O
Biologi: -
H. CONCLUTION
From lab work we have done, we can conclude that :
1. We can design molecule shape with tools and materials from any
equipment that store around us.
2. Size diameter of atom C : 7cm, diameter of atom H: 3,5cm, length of
water 10,9 cm and size angle of methane molecule or CH4 is 109.5 o
Size diameter of atom O : 6cm, diameter of atom H: 3,5cm, length of
water 9,6 cm and size angle of water molecule or H2O is 104,5 o.
I. ANSWER THE QUESTION
1. Molecule of methane and water consist of some atom, explain the atom
that arrange methane and water !
Answer : methane (CH4) is formed from the C atom having atomic
number 6 and H atoms which have an atomic number, atomic C still
has 4 electrons that have not bonded, so that stable C atom bonded to 4
H atoms, and form a covalent bond. Water (H2O) is formed from the
O atom has atomic number 8 and H atoms with atomic number 1. O
atom still has two electrons are bound, so that stable O atoms bonded
to two H atoms with covalent bonds.
2. Mention a molecule shape of methane and water !
Answer : molecule shape of methane is tetrahedran, and molecule
shape of water is polymer.
3. How the bond length to the hand, the diameter of each atom and the angle
between atoms ?
Answer : in the form of methane molecules made of one hand is
longer than the other hand, while on the water molecules form the
same size arm length. The angle between the molecular form methane
and water molecule are different, the methane molecule has a
a shrinkage of 109.50 while the water molecule have an angle 109. 570.
Diameter balls made different is the diameter of the ball that the
center (on the methane molecule) made larger with clay coated, while
the diameter of the ball in each hand is the same. The diameter of the
ball in the middle (on the water molecules) made larger than his
hands. On the second ball is the same of hand.
J. REFERENCES
Cahyo, Agus Nur. 2008. Molekul Air. Diakses pada 31 Oktober 2011 dari
http://agusnurch.wordpress.com/2008/09/24/sub-bab-213-molekulair/
Eko. 2010. Atom, Molekul dan Ion. Diakses pada 31 Oktober 20111 dari
http://ekocin.wordpress.com/2010/06/03/makalah-atom-molekuldan-ion/
Praweda. 2011. Kimia. Diakses pada 2 November 2011 dari
http://bebas.ui.ac.id/v12/sponsor/SponsorPendamping/Praweda/Kimia/0235b%20Kim%202-12f.htm
Sukardjo.1992. Kimia Koordinasi. Jakarta : Rineka Cipta
Wijayanti. 2009. Bentuk Molekul. Diakses pada 2 November 2011 dari
http://kimia-asyik.blogspot.com/2009/12/bentuk-molekul.html
K. DOKUMENTASI
DESIGN MOLECULE