Packet F: Bonus 2
This crystal structure is the most stable configuration for cadmium selenide nanoparticles used to assemble quantum dots. For 10 points each:
[10h] Name this structure composed of tetragonal unit cells arranged in a hexagonal close-packing configuration. Sphalerite can be transformed into this structure by heating zinc sulfide crystals at over 1,000 degrees Celsius.
ANSWER: wurtzite [accept cadmoselite or greenockite or máitrete; prompt on w]
[10m] Gallium and this species form wurtzite crystals used in blue LEDs, whose development won the 2014 Nobel Prize in Physics. Hexagonal crystals of boron and this species form ferroelectric “white graphene” monolayers.
ANSWER: nitride [or N3−; accept gallium nitride or GaN; accept boron nitride or BN; reject “nitrogen” or “nitrate” or “nitrite”]
[10e] Analogous to diamond, boron nitride in its sphalerite form has this crystal geometry system instead, whose face-centered type has an atomic packing factor about 0.06 larger than its body-centered type.
ANSWER: cubic [accept cube; accept face-centered cubic or fcc; accept body-centered cubic or bcc; accept cubic closed-packed or ccp]
<Chicago B, Chemistry> | Packet F - Chicago C, McGill C, WashU A, Chicago B
| Heard | PPB | E % | M % | H % |
|---|---|---|---|---|
| 85 | 9.65 | 78% | 14% | 5% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| Central Florida B | Florida A | 0 | 0 | 10 | 10 | E |
| Florida B | Central Florida A | 0 | 0 | 0 | 0 | |
| Florida C | Central Florida C | 0 | 0 | 10 | 10 | E |
Summary
| Tournament | Edition | Match | Heard | PPB | E % | M % | H % |
|---|---|---|---|---|---|---|---|
| California (North) | Main Site | ✓ | 3 | 20.00 | 100% | 33% | 67% |
| California (South) | Main Site | ✓ | 4 | 10.00 | 75% | 25% | 0% |
| Canada | Main Site | ✓ | 10 | 9.00 | 70% | 10% | 10% |
| Florida | Main Site | ✓ | 3 | 6.67 | 67% | 0% | 0% |
| Great Lakes | Main Site | ✓ | 5 | 14.00 | 100% | 40% | 0% |
| Lower Mid-Atlantic | Main Site | ✓ | 9 | 8.89 | 78% | 11% | 0% |
| Midwest | Main Site | ✓ | 8 | 10.00 | 88% | 13% | 0% |
| Northeast | Main Site | ✓ | 6 | 11.67 | 83% | 33% | 0% |
| Overflow | Main Site | ✓ | 4 | 7.50 | 75% | 0% | 0% |
| South Central | Main Site | ✓ | 2 | 5.00 | 50% | 0% | 0% |
| Southeast | Main Site | ✓ | 7 | 10.00 | 86% | 14% | 0% |
| UK | Main Site | ✓ | 12 | 6.67 | 58% | 8% | 0% |
| Upper Mid-Atlantic | Main Site | ✓ | 8 | 10.00 | 88% | 13% | 0% |
| Upstate NY | Main Site | ✓ | 4 | 10.00 | 75% | 0% | 25% |