On ACRES's Candlelight Vigil for Wenwen

in , ,

Source credit: ACRES
Animal Concerns Research and Education Society (ACRES) is organising a candlelight vigil and memorial service for Wen Wen, a dolphin which died during transportation to the Resorts World Sentosa.

This event will be held on Sunday, 2 December 2012, 6 pm at Hong Lim Park (Speaker's Corner). Please attend if you have the time.

Due to examinations on the subsequent day, I decided to forgo the opportunity of attending this vigil.

What struck me was a Facebook update by one of my acquaintance. It was aloof, even disdainful. 

How is it that he can get away with such a comment and even have 14 of his FB friends 'Like' his post?

What gives him the right to view the issue from a vantage of moral superiority?

Has he even actively dedicated a significant portion of his time, energy and money to helping those in need?

Does he expect everyone to conform to his worldview? And what does he mean by 'those men are real jokers'?!

In such an absolute worldview that does not account for others' experiences and passions, there is intolerance. And in this intolerance, there is an unnerving repugnance. Just re-reading his FB post may cause a series of cardiac arrests.

I mean, I'd like for the dolphins to be free. However, I'm not willing to devote myself to campaigns to free them. So yes, I'm lazy in this regard. However, at least, I don't go about dismissing the efforts by environmental advocates. I respect them for being willing to stand up against the exploitation of the voiceless.

Hence, to the people who casually dismiss others' efforts:
Shame on you.

*
By the way, I wanted to share this video too:

0 comments:

Really Bad Analogies Written by High School Students

in ,

Saw the below list of analogies and felt that I should share it. How I wish my tuition kids would write something like this for me. Hmm, I'd probably have a heart attack if they wrote like that though - a heart attack that feels like... a constipation unexpectedly becoming diarrhoea.


Her eyes were like two brown circles with big black dots in the center.

He was as tall as a 6′3″ tree.

Her face was a perfect oval, like a circle that had its two sides gently compressed by a Thigh Master.

From the attic came an unearthly howl. The whole scene had an eerie, surreal quality, like when you’re on vacation in another city and Jeopardy comes on at 7:00 p.m. instead of 7:30.

John and Mary had never met. They were like two hummingbirds who had also never met.

She had a deep, throaty, genuine laugh, like that sound a dog makes just before it throws up.

The ballerina rose gracefully en pointe and extended one slender leg behind her, like a dog at a fire hydrant.

He was as lame as a duck. Not the metaphorical lame duck, either, but a real duck that was actually lame. Maybe from stepping on a land mine or something.

Her vocabulary was as bad as, like, whatever.

She grew on him like she was a colony of E. coli and he was room-temperature Canadian beef.

The revelation that his marriage of 30 years had disintegrated because of his wife’s infidelity came as a rude shock, like a surcharge at a formerly surcharge-free ATM.

The lamp just sat there, like an inanimate object.

McBride fell 12 stories, hitting the pavement like a Hefty bag filled with vegetable soup.

His thoughts tumbled in his head, making and breaking alliances like underpants in a dryer without Cling Free.

He spoke with the wisdom that can only come from experience, like a guy who went blind because he looked at a solar eclipse without one of those boxes with a pinhole in it and now goes around the country speaking at high schools about the dangers of looking at a solar eclipse without one of those boxes with a pinhole in it.

Long separated by cruel fate, the star-crossed lovers raced across the grassy field toward each other like two freight trains, one having left Cleveland at 6:36 p.m. traveling at 55 mph, the other from Topeka at 4:19 p.m. at a speed of 35 mph.

Shots rang out, as shots are wont to do.

The little boat gently drifted across the pond exactly the way a bowling ball wouldn’t.

Her hair glistened in the rain like nose hair after a sneeze.

They lived in a typical suburban neighborhood with picket fences that resembled Nancy Kerrigan’s teeth.

Even in his last years, Grand pappy had a mind like a steel trap, only one that had been left out so long, it had rusted shut.

He felt like he was being hunted down like a dog, in a place that hunts dogs, I suppose.

She was as easy as the TV Guide crossword.

She walked into my office like a centipede with 98 missing legs.

The plan was simple, like my brother-in-law Phil. But unlike Phil, this plan just might work.

The young fighter had a hungry look, the kind you get from not eating for a while.

“Oh, Jason, take me!” she panted, her breasts heaving like a college freshman on $1-a-beer night.

It hurt the way your tongue hurts after you accidentally staple it to the wall.

It was an American tradition, like fathers chasing kids around with power tools.

He was deeply in love. When she spoke, he thought he heard bells, as if she were a garbage truck backing up.

Her date was pleasant enough, but she knew that if her life was a movie this guy would be buried in the credits as something like “Second Tall Man”.

The thunder was ominous-sounding, much like the sound of a thin sheet of metal being shaken backstage during the storm scene in a play.

She caught your eye like one of those pointy hook latches that used to dangle from screen doors and would fly up whenever you banged the door open again.

Her pants fit her like a glove, well, maybe more like a mitten, actually.

Fishing is like waiting for something that does not happen very often.

They were as good friends as the people on “Friends.”

Oooo, he smells bad, she thought, as bad as Calvin Klein’s Obsession would smell if it were called Enema and was made from spoiled Spamburgers instead of natural floral fragrances.

The knife was as sharp as the tone used by Rep. Sheila Jackson Lee (D-Tex.) in her first several points of parliamentary procedure made to Rep. Henry Hyde (R-Ill.) in the House Judiciary Committee hearings on the impeachment of President William Jefferson Clinton.

He was as bald as one of the Three Stooges, either Curly or Larry, you know, the one who goes woo woo woo.

Her eyes were shining like two marbles that someone dropped in mucus and then held up to catch the light.

I felt a nameless dread. Well, there probably is a long German name for it, like Geschpooklichkeit or something, but I don’t speak German. Anyway, it’s a dread that nobody knows the name for, like those little square plastic gizmos that close your bread bags. I don’t know the name for those either.

She was as unhappy as when someone puts your cake out in the rain, and all the sweet green icing flows down and then you lose the recipe, and on top of that you can’t sing worth a damn.

It came down the stairs looking very much like something no one had ever seen before.

Bob was as perplexed as a hacker who meant to access T:flw.quid55328.com\aaakk/ch@ung but got T:\flw.quidaaakk/ch@ung by mistake.

The dandelion swayed in the gentle breeze like an oscillating electric fan set on medium.

The sunset displayed rich, spectacular hues like a .jpeg file at 10 percent cyan, 10 percent magenta, 60 percent yellow and 10 percent black.

0 comments:

My Growth As A Poet

in ,

Recently, I took a module on writing poetry. As part of the assessment, I was supposed to reflect on what I've learnt.

My feelings came out, crashing. After typing out the last phrase, I felt like paper - frail, thin and all too transparent. So much ink has flowed, a splattered mess.

My Growth As A Poet

At the start of the semester, I received an email from USP. Out of idle interest, I clicked on a weblink and began to read an article. It was an interview of Professor Shirley Lim by then poet-in-residence Jay Bernard. I was fascinated by the interview and wondered, could I handle the workload of a module that I did not need to take but want to. Perhaps I should try. Anyway, I can always drop it by the third week of school if it isn’t what I expect.

Fortunately, this module wasn’t what I expected. It was so much more. I learnt to allow myself to make mistakes, to allow myself to continue writing even when the first word, the first line was imperfect. I learnt to be more comfortable with failing and struggling. I have also learnt to be humble in my choice of words, to speak without affection or pretention, to write with clarity and an economy of words.

But this module is more than just writing poems. It is an experience all the more richer and beautiful because we have a community, a safe space where we can examine our experiences, dreams and disappointments. We deal with issues that trouble or inspire us – our parents whom we’ve argued with, the Jaguars prowling the roads, the relentless competition in school. We are able to do that because we trust each other. There is a safe space where we can be.

Once, at night, a group of four male friends crowded around my laptop and, with their relentless stream of ‘encouragement’, I read some of my poems aloud. One friend commented that my poems are nice but they’re hardly memorable. Another friend told me that I ought to have two beautiful lines per poem that readers can remember readily. Well, it’s always good to know where I can improve. However, the conversation – only because it was an all-guys conversation – quickly moved on to comments like why are you forever writing such sensual and sexual poems? Are the molecules having sex? Is that poem about a French kiss? I was being trolled by playful, albeit somewhat immature, guy friends. I smacked my forehead and left my palm there while I tried to suppress a grimace. How can a poem on repressed, ambivalent answers become one on a French mouth-to-mouth? Urgh.

During Recess Week, while waiting at the bus stop, I saw Peter and we chatted. We started talking about this module and our chapbooks. Peter asked me if I wrote poems before this class. How should I answer? We aren’t very close friends and I’m fearful of being vulnerable. Back when I was serving national service, my bunkmates Googled my name and found a poem – a really bad one on the summer breeze – that I wrote when I was in secondary school. They had a field day making fun of me.

“Yes, I did write poems before this class.” It turned out that many of us were already writing ever since we first encountered literature in our secondary schools. It was as though we were quietly writing poems in our little corners, waiting for someone to come along and guide us.

In the deserts, there would be sudden thunderstorms unleashing copious amount of water. Seeds that have been lying dormant would suddenly sprout leaves and flower magenta blossoms. The entire landscape, once barren, sandy and desolate, would be a purple sea. It feels as though that’s what that had happened for this class. We were ready for the nourishing rain.

One moment that I could remember was the night Stella and I arranged the poems for Red Pulse. We were tired but thought that we ought to write a filler for the Editors’ Note before posting the manuscript online. She tossed out one line and I added another. Line by line, our ‘prose poem’ (or what Cara called the ‘Faux Editors’ Note’) took shape:
It has been a life-changing experience and we were shaped into sculptures symbolizing universal equality and brotherhood of Mankind. As Universal Scholarly People, we were – and still are – appreciated like the sculptures of elegance and beauty that we have been chiseled into. In our sacrificial service as Editors, we have grown green and strong under the brilliant sunlight of the Shirley, just as the grass in Town green has so thrived on the soils of Knowledge. This anthology heralds the winds of change that will billow throughout NUS, Singapore, its hinterlands and the Milky Way.
Thanks, Prof Lim, we aren’t joking when we said that ‘we have grown green and strong under the brilliant sunlight of the Shirley’.

My heart (er-hem) began to hum a song, one that I couldn’t mute. I’ve spent much time running away from the arts. It is impractical and doesn’t bring in the moolah. I’m from an average family. I need to do well academically. There are so many starving artists, so many stories of starving artists.

Yet, the heart sang. I wanted to ignore the song, to stifle or suffocate it. It wasn’t because I didn’t like this melody. I loved it. But it was because I couldn’t afford the time or energy or money to enjoy its cadence. There were lab reports to do, research to conduct, papers to read, a new language to pick up, a Chemistry professor to placate, five students to tutor on the weekends. There were roles that had been scripted for me, that I was supposed to fit and play out accordingly. How I wish that the song could be recorded and replayed at will.

Have I allowed what I wanted to slowly wither away? Too tired to push against the circumstances, too timid to resist the expectations? I think so, I really think that part of me had went away, been lost along the way. This module – this opportunity, this gift – has reminded me that I once dreamt and ought to continue dreaming. So, thanks, thanks, Prof Lim, for radiating light and guiding us to become better people.

Ever Pulsing. Cover art by The Gentlemen's Press.

0 comments:

Advice to a Friend

in

(This is just a filler piece. Please don't take it too seriously. :)

A few days ago, I had breakfast with a male friend. It was a so-so meal, with cereal and milk. Then, he told me that he wanted to visit a nudist beach when he goes on an exchange next semester. "After all," he mentioned casually, "the beach will be really near my exchange uni and it's quite convenient to go. I want to see how it's like."

I wondered how to dissuade him for a while and decided that I had no business dictating what he ought to do (or not do). "Just be careful," I advised. "Don't let people take a photo or video of you without your knowledge. Might somehow affect your job prospects next time."

My eyebrows raised and the real reason barreled out of my pursed lips. "You don't want them to use the footage in a horror movie. You do know that you bear a slight resemblance to Arnold Schwarzenegger's affair, right?"

Picture of Arnold Schwarzenegger's affair. Source credit: California News
He has since described me in many unflattering terms.

0 comments:

Memes on Science - "Trust me, I'm a Biologist"

in

Saw these memes on Trust me, I'm a Biologist and thought that they were really witty.

A very literal Heart.

Most atoms are into bondage. They are prehistoric in this way.

Very scary. Wooooooo-

My favorite.

0 comments:

Red Pulse, 2012

in

Stella and I are designers for Red Pulse, a collection of beautiful poems. This collection is the culmination of our collective efforts in the ULT2298E: Chapbooks and Digital Poetry: Poetics Mash-Up class.

As designers, we exercised our prerogative and wrote a humorous editors' introduction. Quite a number of our classmates, including our lecturer Prof Shirley Lim, got an early Christmas surprise.

Designers-Faux Editors' Note 
 

It has been a life-changing experience and we were shaped into sculptures symbolizing universal equality and brotherhood of Mankind. As Universal Scholarly People, we were – and still are – appreciated like the sculptures of elegance and beauty that we have been chiseled into. In our sacrificial service as Editors, we have grown green and strong under the brilliant sunlight of the Shirley, just as the grass in Town green has so thrived on the soils of Knowledge. This anthology heralds the winds of change that will billow throughout NUS, Singapore, its hinterlands and the Milky Way.
*
For some reason, no one wanted the above introduction to be used. Come on, we thought that it was a fascinating piece, one bound to raise many eyebrows. At any rate, Cara - she's one of the real editors - felt an impetus to write a proper introduction during class time after reading what was written.

What The Real Editors Wrote

“One class rule: when you step through the saloon doors, leave your guns at the door!”

With a class introduction like that, we knew this semester was going to be pretty special. For four hours each week, we had the opportunity to come into a common space, “leave our guns at the door”, and be honest—with ourselves, with each other, and in our art.

Shirley’s (or Prof Lim, to some) guidance and poetic philosophy have been invaluable in fostering a spirit of camaraderie among us writers. We came to realize the importance of a writing community as a safe sharing space in which we could completely and comfortably immerse ourselves in the stories that we would go on to tell through our craft as poets. Red Pulse is an extension of that. Its creation has been an amazing journey, and a testament to how great things can begin in small ways.

As editors helming the production of Red Pulse, we never thought putting together an anthology would be so difficult, but it was. We did, however, think it would be worthwhile—and it has been, thrice over. The call for submissions garnered a fantastic response, and we received numerous poems that we were eager to showcase in the anthology. After making our selection, we spent one night moving poems around until we came up with our five chapters and their titles. By then, people were already stepping forward to offer their skills and services—whether as copy editors, illustrators, designers, or production managers. It was heartwarming to see the whole class claim their share in the weaving together of Red Pulse.

The poems that you will read in this anthology are diverse. Some of them are indubitably Singapore poems, commentaries on the city state that we call home. Some of them are about family, love, friendship. Some of them are poems that exalt the abstract; some are derived from the minutiae of the everyday, which one might overlook. What underscores all of these various voices, however, is a whole lot of heart. This is a collection of honest poetry that seeks to sustain and to revitalize the proverbial Red Pulse, the creative impulses that have animated our lives in this little red dot.

We hope you will enjoy this collection.
*
The above editors' note by Cara and Jun Sheng resonated. This module on crafting poetry has been an eye-opener. We've learned the value and power of a single word. We've formed a community where we could allow ourselves to be vulnerable, a community where we could examine our experiences without fear or judgement. We spoke about the past that have brought us love, gave us joy and scarred us. We talked about our hopes and dreams.

I'm grateful for the opportunity to take this module under Prof Lim and with my new-found friends. 


Red Pulse, 2012

0 comments:

Lab Report on Preparation and Magnetic Properties of some Ni(II) Complexes

in

The lab report below was submitted as part of the coursework for CM2111 Inorganic Chemistry. Please do not plagiarise from it as plagiarism might land you into trouble with your university. Do note that my report is well-circulated online and many of my juniors have received soft copies of it. Hence, please exercise prudence while referring to it and, if necessary, cite this webpage.
Aim
To examine the effects of the axial ligands on the electronic structures of 4 prepared Ni(II) tetragonal complexes, with electronic spectroscopy and magnetic susceptibility determination.
Procedures
Preparation of Ni complexes
The samples were prepared carefully, according to instructions from the lab manual.

Investigations of the complexes – Electronic Spectra
0.1194g of sample A synthesised, Ni(Et2en)2Cl2.2H2O, was weighed using the 10ml dry volumetric flask before methanol was added with a dropper, until the volume made up to the mark of the volumetric flask. The procedures were repeated, this time with 0.1222g of sample B synthesised, Ni(Et2en)2(NCS)2, and CH2Cl2 as solvent. Both of the volumetric flasks were shaken before pouring each into a clean cuvette to record their electronic spectra.

Investigations of the complexes – Magnetic Properties
All four complexes were first grinded to a fine, uniform powder. Thereafter, the mass of the clean, dried sample tube was first determined. Each sample was then loaded into the tube, with gentle tapping before the next addition to ensure close and even packing. Next, the mass of the sample tube with the sample was weighed to get the mass of each sample present in the tube as well as measuring the length till which the sample filled the sample tube. The magnetic moments of the complexes were then determined using the magnetic susceptibility balance.

Results and calculations
  1. Ni(Et2en)2Cl2.2H2O

Mass of NiCl2.6H2O  used /g
0.79
Mass of Et2en used /g
0.77
Mass of Ni(Et2en)2Cl2.2H2O formed / g
1.24

NiCl2.6H2O + 2Et2en Ni(Et2en)2Cl2.2H2O + 4H2O
Mr. of NiCl2.6H2O = 58.69 + 2 × 35.45 + 6 × [2 × (1.01) +16.00]= 237.71
No. of moles of NiCl2.6H2O used = mass / Mr = 0.79 / 237.71 = 3.32 x 10-3 mol
Mr of Et2en, (CH3CH2)2NCH2CH2NH2 = 14.01 x 2 + 12.01 x 6 + 16 x 1.01= 116.24
No. of moles of Et2en used = mass / Mr = 0.77 / 116.24 = 6.62 x 10-3 mol
No. of moles of NiCl2.6H2O required = ½ x 6.62 x 10-3 = 3.31 x 10-3 mol Et2en is the limiting reagent.
No. of moles of Ni(Et2en)2Cl2.2H2O formed = 3.31 x 10-3 mol
Mr of Ni(Et2en)2Cl2.2H2O = 58.69 +116.24 x 2 + 35.45 x 2 +2 x (16.00+2 x 1.01) = 398.11

Theoretical yield of Ni(Et2en)2Cl2.2H2O = 3.31 x 10-3 x 398.11 = 1.32 g
Percentage yield of Ni(Et2en)2Cl2.2H2O =1.24 / 1.32 x 100 %  = 93.9%

  1. Ni(Et2en)2(NCS)2

Mass of NaNCS used /g
0.54
Mass of Et2en used /g
0.77
Mass of Ni(Et2en)2(NCS)2 formed /g
1.27

Ni(NO3)2.6H2O + 2NaNCSà Ni(NCS)2.4H2O + 2H2O + 2NaNO3
Mr of Ni(NO3)2.6H2O =  58.69 + 2 × 14.01 + 6 × 16.00 + 6 x [2 × (1.01) +16.00]= 290.83
No. of moles of Ni(NO3)2.6H2O used = mass / Mr = 0.97 / 290.83 = 3.34 x 10-3 mol
No. of moles of NaNCS used = mass / Mr = 0.54 / (22.99 + 14.01 + 12.01 + 32.07) = 6.66 x 10-3 mol
No. of moles of Ni(NO3)2.6H2O required = ½ x 6.66 x 10-3 = 3.33 x 10-3 mol\NaNCS is the limiting reagent.
No. of moles of Ni(NCS)2.4H2O formed = 3.33 x 10-3 mol

Ni(NCS)2.4H2O + 2Et2enà Ni(Et2en)2(NCS)2 + 4H2O
No. of moles of Et2en used = mass / Mr = 0.77 / 116.24 = 6.62 x 10-3 mol
No. of moles of Ni(NCS)2.4H2O required = ½ x 6.62 x 10-3 = 3.31 x 10-3 mol \ Et2en is the limiting reagent.
No. of moles of Ni(Et2en)2(NCS)2 formed = 3.31 x 10-3 mol
Mr of Ni(Et2en)2(NCS)2 = 58.69 + 116.24 x 2+ 2 x (14.01 + 12.01 + 32.07) = 407.35

Theoretical yield of Ni(Et2en)2(NCS)2 = 3.31 x 10-3 x 407.35 = 1.35 g
Percentage yield of Ni(Et2en)2(NCS)2 = 1.27 / 1.35 x 100 %  = 94.1%

(C)Ni(Et2en)2(NO3)2

Mass of Ni(NO3)2.6H2O  used /g
0.97
Mass of Et2en used /g
0.77
Mass of Ni(Et2en)2(NO3)2 formed /g
1.10

Ni(NO3)2.6H2O + 2Et2enà Ni(Et2en)2(NO3)2 + 6H2O

No. of moles of Ni(NO3)2.6H2O used = mass / Mr = 0.97 / 290.83 = 3.34 x 10-3 mol
No. of moles of Et2en used = mass / Mr = 0.77 / 116.24 = 6.62 x 10-3 mol
No. of moles of Ni(NO3)2.6H2O required = ½ x 6.62 x 10-3 = 3.31 x 10-3 mol \ Et2en is the limiting reagent
No. of moles of Ni(NO3)2.6H2O formed = 3.31 x 10-3 mol
Mr of Ni(Et2en)2(NO3)2 = 58.69 + 116.24 x 2 + 14.01 x 2 + 6 x 16.00 = 415.69

Theoretical yield of Ni(Et2en)2(NO3)2 = 3.31 x 10-3 x 415.69 = 1.38 g
Percentage yield of Ni(Et2en)2(NO3)2  = 1.10 / 1.38 x 100 %  = 79.7%

(D)Ni(Et2en)2I2

Mass of NaI used /g
1.05
Mass of Et2en used /g
0.77
Mass of Ni(Et2en)2I2 formed /g
1.29

Ni(NO3)2.6H2O + 2NaIà NiI2.4H2O + 2H2O + 2NaNO3
No. of moles of Ni(NO3)2.6H2O used = mass / Mr = 0.97 / 290.83 = 3.34 x 10-3 mol
No. of moles of NaI used = mass / Mr = 1.00 / (22.99 + 126.90) = 6.67 x 10-3 mol
No. of moles of NaI required = 2 x 3.34 x 10-3 = 6.68 x 10-3 mol \NaI  is the limiting reagent
No. of moles of NiI2.4H2O formed = 3.34 x 10-3 mol

NiI2.4H2O + 2Et2enà Ni(Et2en)2I2 + 4H2O
No. of moles of Et2en used = mass / Mr = 0.77 / 116.24 = 6.62 x 10-3 mol
No. of moles of NiI2.4H2O required = ½ x 6.62 x 10-3 = 3.31 x 10-3 mol \ Et2en is the limiting reagent
No. of moles of Ni(Et2en)2I2 formed = 3.31 x 10-3 mol
Mr of Ni(Et2en)2I2 = 58.69 + 116.24 x 2 +126.90 x2 = 544.97

Theoretical yield of Ni(Et2en)2I2 = 3.31 x 10-3 x 544.97 = 1.80 g
Percentage yield of Ni(Et2en)2I2 =1.29 / 1.80 x 100% = 71.7%

Electronic Spectra
In order to prepare 3.00 x 10-2 M solutions,
no. of moles of Ni(Et2en)2Cl2.2H2O / Ni(Et2en)2(NCS)2 needed = 3.00 x 10-2 x 10.0 /1000  = 3.00 x 10-4 mol

Mass of A, Ni(Et2en)2Cl2.2H2O needed  = 3.00  x 10-4 x 398.04 = 0.1194 g Mass of A used: 0.1194 g Results from UV-Vis spectra for A:
Wavelength
Absorbance
671.00 nm
0.2390
398.00 nm
0.6664

Mass of B, Ni(Et2en)2(NCS)2 needed = 3.00  x 10-4 x 407.26 = 0.1222 g Mass of B used: 0.1222 g
Results from UV-Vis spectra for B:
Wavelength
Absorbance
581.50 nm
0.3600
368.00 nm
0.7500

Determination of magnetic moment and number of unpaired electrons
Compound
A
B
C
D
Mass of sample /g
0.09030
0.0852
0.0881
0.0892
Length /mm
19.0
20.0
19.0
16.0
Magnetic susceptibility, cg
0.074 x10-4
0.066 x 10-4
0.000 x 10-4
0.000 x 10-4

  1. Ni(Et2en)2Cl2.2H2O
cm = cg x MW + cD + cTIP  = cg x MW + CNi2+ + 2CCl- + 2CEt2en + 2CH2O
= (0.074 x 10-4) x 398.038 + [12.8 + (2 x 23.4) + (2 x 46) + (2 x 13)] x 10-6
= 3.123 x 10-3 cm3 mol-1
m =  =  = 2.730 J T-1
m =                       2.7302 = n2 + 2n                        n = 1.91   2
No. of unpaired electrons in Ni(Et2en)2Cl2.2H2O = 2

  1. Ni(Et2en)2(NCS)2
cm = cg x MW + cD + cTIP = cg x MW + CNi2+ + 2CNCS- + 2CEt2en
= (0.066 x 10-4) x 407.33 + [12.8 + (2 x 31.0) + (2 x 46)] x 10-6
               = 2.855 x 10-3 cm3 mol-1
m =  =  = 2.610 J T-1
m =              n2 + 2n – 2.6102 = 0           n= 1.80 » 2
\No. of unpaired electrons in Ni(Et2en)2(NCS)2 = 2

  1. Ni(Et2en)2(NO3)2
cm = cg x MW + cD + cTIP = cg x MW + CNi2+ + 2CNO3- + 2CEt2en
               = 0 + [12.8 + (2 x 46) + (2 x 18.9)] x 10-6 = 1.426 x 10-4 cm3 mol-1
m =  =  = 0.583 J T-1
m =             0.5832 = n2 + 2n n= 0.158 » 0
\No. of unpaired electrons in Ni(Et2en)2(NO3)2 = 0
  1. Ni(Et2en)2I2
cm = cg x MW + cD + cTIP = cg x MW + CNi2+ + 2CI- + 2CEt2en
= 0.000  + [12.8 + (2 x 50.6) + (2 x 46)] x 10-6 = 2.06 x 10-4 cm3 mol-1
m =  = = 0.701 J T-1
m =    0.7012 = n2 + 2n n= 0.221 » 0
\No. of unpaired electrons in Ni(Et2en)2I2 = 0
Discussion
Colour of Ni complexes
In this experiment, the obtained Ni(Et2en)2Cl2.2H2O crystals are light-blue; Ni(Et2en)2(NCS)2 are violet crystals; Ni(Et2en)2(NO3)2 is yellow and Ni(Et2en)2I2, red-orange.
These nickel complexes are coloured because they absorb light in the visible region. Absorption of energy from the visible light region of the electromagnetic spectrum occurs when an electron is promoted from a d-orbital in nickel of lower energy to a higher energy. The colour of the compound observed is the complementary colour of the absorbed colour of the visible light.
UV/VIS spectra in terms of electronic structure

Ni(II) has a d8 electronic configuration at ground state with 3F term. The associated energy levels arising from crystal field splitting arranged from low to high are A2g, T2g, T1g(F) and T1g (P).  There are only 3 possible transitions arranged from small energy gap to big energy gap: 3T2g3A2g,   3T1g (F)  3A2g and 3T1g (P) 3A2g. Since the magnitude of wavelength of light absorbed is inversely proportional to the magnitude of the energy gap, hence 3T1g (P) 3A2g occurs at the shortest wavelength followed by 3T1g (F) ß 3A2g then 3T2g ß3A2g.
The spectra of Ni(Et2en)2Cl2.2H2O (as attached) contains 2 peaks at 671.00nm and 398.00nm. The absorbed light of  wavelength 671.00nm corresponds to the 3T1g (F) ß 3A2g transition while that at 398.00nm corresponds to the 3T1g (P)ß 3A2g transition.
The spectra of Ni(Et2en)2(NCS)2 (as attached) contains 2 peaks at 581.50nm and 368.00nm. For this nickel(II) complex, the absorbed light of  wavelength 581.50nm corresponds to the 3T1g (F) ß 3A2g transition while that at 368.00nm corresponds to the 3T1g (P)ß 3A2g transition.  
Ni(II) complexes having d8 configurations with P and F terms can undergo 3 transitions, which correspond to 3 absorption peaks in theory. However, only 2 peaks are present for all the obtained spectra. This is because the wavelength used in the UV-visible spectrophotometer is 350 nm to 800nm and the ‘missing’ peak may lie outside this range.
Et2en is a bidentate ligand that occupies the equatorial position due to the short C-C bond which cannot stretch across axial-equatorial. For these Ni complexes, the main difference among the 4 complexes is the 2 axial ligands. A stronger field ligand will cause a greater splitting of the energy states and hence a greater value for the transitions, translating to more energy required and hence shorter wavelength for absorption to take place. From the spectra, for the same transition of 3T1g (P)ß 3A2g, the maximum absorption occurs at 368.00nm for Ni(Et2en)2(NCS)2, 398.00nm for Ni(Et2en)2Cl2.2H2O, 455.00nm for Ni(Et2en)2(NO3)2 and 475.00nm for Ni(Et2en)2I2 in increasing wavelengths. Hence, it can be deduced that the ligand-field strengths are follows: NCS->Cl->NO3->I-. This observation is in line with the spectrochemical series except for NO3- which is supposed to be stronger than that of Cl-. One possible reason for this deviation could be due to binding competition from the Et2en chelate or affinity of the central Ni ion for certain ligands.
Magnetic properties in terms of electronic configuration
As seen from the calculations above, Ni(Et2en)2Cl2.2H2O and Ni(Et2en)2(NCS)2 are paramagnetic due to the presence of 2 unpaired electrons. It can be inferred that they would most probably adopt the high-spin configuration. However, Ni(Et2en)2(NO3)2 and Ni(Et2en)2I2, with no unpaired electrons, would adopt the low-spin configuration.

Ni(Et2en)2Cl2.2H2O and Ni(Et2en)2(NCS)2 undergo weak tetragonal distortions to form tetragonal geometry while Ni(Et2en)2(NO3)2 and Ni(Et2en)2I2 undergo strong tetragonal distortions to form square planar structures.

For tetragonal complexes, Ni(Et2en)2Cl2.2H2O and Ni(Et2en)2(NCS)2, a1g and b1g orbitals are close in energy, hence the last 2 electrons fill in the orbitals singly rather than pair up in a1g orbitals. There are 2 unpaired electrons in the complexes, therefore accounting for their paramagnetism. This corresponds to experimental findings. The complexes will be attracted to magnetic fields and carry magnetic moment due to the large energy difference resulting from the strong field ligands which causes the pairing energy of the electrons to be negligible and hence the electrons will attain a high spin configuration.

For square planar complexes, Ni(Et2en)2(NO3)2  and Ni(Et2en)2I2 , since b1g and b2g orbitals are far apart in energy, the last 2 electrons will pair up given that the pairing energy is sufficient to compensate for the energy gap to exhibit low spin configuration. There are no unpaired electrons in these 2 complexes, thereby resulting in zero magnetic susceptibility. This corresponds to the experimental results.

As a result, both the electronic configurations of Ni(Et2en)2(NCS)2 and Ni(Et2en)2Cl2.2H2O complexes are eg4 b2g2 a1g1b1g1. The electronic configurations for that of Ni(Et2en)2I2  and Ni(Et2en)2(NO3)2 complexes are both eg4 a1g2b2g2.

Precautions
All apparatus were thoroughly cleaned with deionised water before use and all measurements were taken with minimal human inherent error. Dry and clean volumetric flasks were used for UV spectroscopy since the presence of water could affect the concentrations of the solutions and the spectra obtained. During the transferring of crystals, it was ensured that as little crystals were lost as possible. When using the magnetic susceptibility balance, the sample was dried and powdered before insertion into the tube; it was loaded in small amounts and the tube was tapped gently on a wooden bench to ensure even packing; the sample was at least 15mm in depth. Meticulous packing of the samples into the tube was important to ensure even distribution of magnetic field when operating the magnetic susceptibility balance.

Yields

The yields of the product are in the range of 71.7% to 94.7%; these yields are not 100% because ligand substitution reactions are reversible. Also, some of the products may have also been lost during transferring. To raise the yield, the solution should be allowed to stand for crystallisation longer and a higher concentration of ligands, used. Minimum amount of ethanol should be used for washing as ethanol will dissolve the crystals, thereby reducing the product yield.
Conclusion
The percentage yields of Ni(Et2en)2Cl2.2H2O, Ni(Et2en)2(NCS)2, Ni(Et2en)2(NO3)2 and Ni(Et2en)2I2 are 93.9%, 94.1%, 79.7% and 71.7% respectively. Both Ni(Et2en)2Cl2.2H2O and Ni(Et2en)2(NCS)2 contain 2 unpaired electrons each and exhibit paramagnetism; Ni(Et2en)2(NO3)2 and Ni(Et2en)2I2 ,however, contain no unpaired electron and do not exhibit paramagnetism.
References
  1. Anonymous, “Crystal Field Theory”, University of West Indies, article retrieved on 25 Jan 2012: http://wwwchem.uwimona.edu.jm/courses/CFT.html

  1. A. Earnshaw, “Introduction to Magnetochemistry”, Academic Press, 1968

0 comments:

Bubbling Joy In Barcelona

Sycophany/ Self-preservation

Romance of the two wisdom teeth

Art Appreciation 101